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Why Not Solid State Hard Drives?
waterlogged asks: "I was just wondering if anybody has heard of a cheap ram based network drive? Seems to me with the ram prices being at about US. $12.00 for 128 megs that someone hasn't developed a battery backup version of this to plug into a network or even a bus. A gig worth of 8ns seek time storage for $120 anyone? That would just about eliminate any wait in loading programs."
BigSlowTarget asks: "There are some previous articles on Slashdot about vendors selling solid state drives, but they all seem to be quite expensive - particularly given the slide in the cost of memory. Has anyone hacked together a solid state drive to take advantage of $60/GB memory prices? I'd really like to be able to boot and run at solid state speed without spending thousands."
Jah-Wren Ryel asks: "In case you haven't noticed, RAM is incredibly cheap, you can put a gigabyte of PC133 RAM into your machine for less than $60. A year ago, that would have cost more like $600. So now it is feasible for one to have a 10-15GB RAM disk, except for one thing - most motherboards won't support more than 2GB total (4 dimm slots x 512MB per dimm). It seems like it wouldn't be too hard to design a PCI card to hold 20-30 dimms and make that available through a hardware windowing scheme (like EMS/EMM back in the old 16-bit days). With the right drivers it could be used as a big RAM disk or for buffercache. Is there such a product out there? The closest I have seen are solid-state disks that sit on the other end of a scsi bus, are too expensive, and aren't anywhere near as fast as a PCI implementation could be."
So what technical details (and the issues of volatile data and price) may be preventing the construction of RAM based drives, and is there anything else that may be preventing some entrepreneurial soul from bringing such a thing to market?
You would still need a stable flow of juice to keep from losing everything in case of a blackout or something. I'll stick to the platters for now.
icksnay on hacking my boxsnay.
I've been saying this for years. Eventually, we need to scrap the spinning platters. Unless I have a butt-load of MP3's and other things I don't really need, I can easily fit most of my stuff into 4GB or less.
Umm.. i hate to be the only pesemist here, but if you build a drive outa plain old SyncRAM, what do you do when the power goes out? I mean, sure there's UPS and the like but, still.
It'd be great for swap space or temp storage... but if that's the case, PUT THE RAM ON THE MOTHERBOARD DUMMY! and if anything, create a ramdisk from that ram!
I wanna BOOT from it.. I'd love to fire up my box hand have the "login:" sitting there after i blink!
(heh. oops.)
Cenatek seems to be on a good track with these. They offer a PCI card with a handful of DIMM slots, a slap on rechargable battery panel, which holds enough power to run a connected hard drive of appropriate size which will dump the contents of what is essentially a RAM disk, in the event of a shutdown or power loss. A little spendy still, for consumer use, but to see something like this backend busy websites, or store database file structures would be pretty slick.
- billn
Okay, add a UPS and all, but wouldn't this still be much less stable than a HD that you can pull out and ship across the country without it losing data?
sulli
RTFJ.
What's the mtbf on Solid state drives? What about power loss? I assume that the memory would have to be non-volitile to meet most needs... that's perhaps where the added expense comes from.
Mmmmmmm. Floor pie!
The most critical one I can think of is this:
If your power fails, you lose all your data.
Doesn't this concern anyone else? RAM requires a bazillion refreshes a second to maintain the data it holds. This needs electricity, folks. Sorry to shoot this down in flames, but come on...
RAM drives are a great idea, the problem is the IDE or SCSI bus. Seek times and retriveal times can be greatly reduced, but the total bandwidth is still a limitation.
Seagate had developed years ago a standard called IPI, I think. It was for the 30 and 40 megabyte RAM drives that had developed. I know it never took off, but it was specificlly for static RAM drives.
What would be really cool, would be RAM storage with an Infiniband interface. Its possible to use it for storage or for regular memory.
Because the kind of RAM you're referring to here is Dynamic RAM (SDRAM) which requires a constant electrical charge in order to maintain the information contained therein-- essentially, your solid state hard drive would need batteries or a power plug separate from the power supply for when the computer is shut off. SRAM, the kind of RAM that would be useful for a solid state hard drive (the kind used for L1 and L2 cache on your processor) is still quite expensive.
where's that Ralph "Jew Hater" Nader guy?
Not that I want to see him return, just wondering.
Slashdot, come for the goatse, stay for the trolls.
Huh? Unless I'm completely out to lunch, I don't see this....
Is my math wrong, or is Cliffs?
Also, how much power does PC133 ram require? Would a rechargeable battery add too much to heat/cost considerations?
This is something I'd be interested in for a number of uses (image editing, etc.)
"Are you on some kind of medication?"
"No"
"Well, you should be."
--Bean
> RAM is now cheaper when it comes to memory-per-unitofcurrency than hard drives
Huh? Where are you buying your RAM and/or hard drives?
60 GB hard drives are available for less than $120-- under $2 per GB.
RAM is approximately $75 per GB.
That seems a bit off from what is claimed.
How many times has your CMOS been wiped out? Sure it happens once in awhile, but that doesn't really have any safeguards. Keeping juice flowing into RAM shouldn't really take too much, but you wouldn't want to let it sit on a shelf for very long.
>I never quite thought I'd see this in my life time, >but RAM is now cheaper when it comes to >memory-per-unitofcurrency than hard drives.
Wha? Last time I checked $200 would get you about 80GB of disk, or 512MB of RAM.
TODO: Something witty here...
Cenatek may make exactly what you're looking for. It's a PCI card, and uses standard SDRAM sticks.
From their site:
The Rocket Drive stores data in memory modules (standard dynamic random access memory, or DRAM) rather than on magnetic media.
Too volitile.
--- RFC 1149 Compliant.
Do the math... hard disk are still 100 times cheaper that RAM.
Oh, and FWIW, you can buy solid-state battery backed RAM based hard-drive technology; you've been able to for years.
L337 script kiddies would no longer have to worry about their Hard Drives telling the tale of all of their l337 ownz3r!ngs. As soon as the feds show up yank the plug.
This would also work for War3z fiends. *again, yanks plug* "What do you mean piracy, I don't even have an OS on there."
Seriously, I think it would only be useful if you could couple it with a RAID-like (I know it wouldn't be true RAID) system so if the power for whatever reason (Power outage, UPS goes bad, battery dies) you info wuold still be there, maybe a RAM-drive that does nightly/hourly back ups...
Note to self: No more arguing with the faithful.
$20 gets you about 256 MB of ram. $200 gets you about 75,000 MB of HD space. Ten times the price gets you 300 times the MBs. What are you smoking, and can you give some of it to my credit card companies?
I never quite thought I'd see this in my life time, but RAM is now cheaper when it comes to memory-per-unitofcurrency than hard drives.
It is? RAM is around $50 for a gig, a hard drive is $300 for 100 gigs, or $3 per gig. RAM doesn't look cheaper to me...
In fact, the Klan is the good nigger's best friend. If the nigger will devote his energies to becoming a better, more useful nigger, rather than the dupe of Northern interests who have caused him to misconstrue his social standing, he will reap the rewards of industry, instead of the disappointments of ambition unobtainable!
Southern whites, occupying that super-position assigned them by the Creator, are justifiably hostile to any race that attempts to drag them down to its own level! Therefore let the nigger be wise in leaving the ballot in the hands of a dominant sympathetic race, since he is far better off as a political eunuch in the house of his friends, than a voter rampant in the halls of his enemies!
We had a Megastore (core memory!) on a PDP11/45 (which was used as the swapping drive, hence upping the category to 11/50, IIRC) back in the 70's. My Nikon Coolpix uses flashram as a formatted dist, something I'm certain other's have noticed. Flashram is able to store and retain with the power off, but doesn't appear to transfer very fast. Using SDRAM would be fast, but only so long as: A) you have a constant source of current B) you don't test/clear on rebooting the CPU. Certainly old ideas, but as long as you can set up a big ramdisk in your OS and put your large temp/workfiles there, do it.
A feeling of having made the same mistake before: Deja Foobar
DRAM is *sooo* much cheaper, and is used in the RAM of just about all computers. However, it's charges "wear out" and needs to be "refreshed" very often. As we all know, data isn't retained in memory when you lose power.
SRAM can "hold" a charge, and is thus more "permanent". I don't have specific quotes, but I know that, compared to conventional RAM, it's insanely expensive. :(
________________________________________________
suwain_2
these guys.
They make solid state disks, which are, for some reason, insanely expensive.
Any sufficiently well-organized community is indistinguishable from Government.
or else it would lose all data if the power goes out. SRAM and Flash ROM are _MUCH_ more expencive per MB that a harddrive is and will most likly stay that way.....for god sake, a 64 MB flash card for your digital camera is $50-$70 can you imagine the cost of a 100GB flash drive?
I am the Alpha and the Omega-3
"640k is enough for everybody" (or something like it) Memories...(I want to hear you all singing)
RAM is now cheaper when it comes to memory-per-unitofcurrency than hard drives.
According to pricewatch, a 40 gig hard drive is $78. Let's say $120 for a good one. That makes RAM 20 times more expensive, at $60/gig.
It's still really cheap, but let's not get crazy. :)
Sometimes it's best to just let stupid people be stupid.
Memory is now cheaper per unit of currency than hard drives
Er, no it isn't. A 100 GB hard drive is $200. 100 gigs of RAM is... a hell of a lot more than that...
- A.P.
"Remember when the U.S. had a drug problem, and then we declared a War On Drugs, and now you can't buy drugs anymore?"
And I'd be a Libertarian, if they weren't all a bunch of tax-dodging professional whiners.
Berke Breathed
Can't comment for other OS, but Linux tends to be pretty good at using all the RAM you've got to cache disk data. Even though I rarely use more than 256 MB, upgrading to 768 MB made a significant performance improvement for me, as Linux quickly fill the remaining 512 MB with disk cache, without me bothering with setting up a ramdrive.
Opus: the Swiss army knife of audio codec
The problem of how to maintain power to all that RAM indefinately is still pretty tricky, but how about this idea. Why not put enough SDRAM on your hard drive to buffer the whole thing? Whenever you read anything off the platters, hold it in RAM, and whenever anything is written, page it back to disk as usual. Thus as you use your system, the speed will continue to improve (up to a point) without tying up system RAM.
There are a lot of reasons. One of them is that it can't replace your current harddrive, because it still is much more expensive. Another reason is that it would require significant rework of your hardware and bios to boot from RAM. And what are you going to do about keeping the data in your permanent-storage-RAM intact? Things can easily go wrong with battery-based solutions.
But, it still sounds like a cool idea. I'd never do it, but let me know if you get it to work...
KemalCan
Don't change.
We like you just the way you are.
Many thousands of people face this problem every day...on their Palm Pilots. If the batteries die, the data goes bye. But as long as you routinely back up the volatile drive on some non-volatile storage media, you're good to go. Given the plummeting price of high density/small footprint hard drives, you could have both the volatile drive and the nonvolatile drive in a single low price unit, with backup to/recovery from the nonvolatile drive occuring automatically on startup and shutdown.
Imagine the size/number of boards that would be needed to get 80 GB of storage. It may be quicker but engineering something that is feasible would quickly drive the cost up so that it wouldn't be that cheap. Further, the cost to modify existing controller technology or making a RAM drive fit the current controllers available. Then there's all kinds of other technical issues like power.
Of course we torture people, we need the information --Gen. Pinochet
If you ever played with a system with enough ram to support mounting a ramdrive on /tmp(and soft link to /usr/tmp etc...Solaris directly maps /tmp into virtual memory/swap??) you see a huge speed up increase for some takes that require generating temporary files.
If there is such a huge speed up why not make devices that act like drives that are really memory? Becuase the software has already been written (ramdrive drivers) and it is faster and cheaper than implimenting a completely seperate piece of hardware and driver.
Also consider the fact that you would have not only create hardware to plug into the SCIS/IDE system, the SCSI and IDE channel bandwidths aren't nearly as good as straight memory. Plus it is nice not to eat sometimes crowded cases with another piece of hardware.
I'm waiting for a nice 80GB EEPROM to store data on.
For a number of years Hitachi has offerred a full line of Solid State drives. The pricing is such that you only see them in very large data centers with serious performance needs.
Perhaps someelse can supply URLs and more details.
80 gig hard drives are less than $2 per gig. The cheapest RAM is at least 50 times that expensive. Look at Price Watch and see for yourself.
Q:How many libertarians does it take to stop a Panzer division? A:None. Obviously market forces will take care of it.
I think that you might need a RAID (or RAIM- M == memory :) for RAM in case one of those dimms decides to die on you. Buggered up platters can be rescued in some cases, but if RAM dies, there's no recovery.
/*drunk.. fix later*/
"I never quite thought I'd see this in my life
time, but RAM is now cheaper when it comes to
memory-per-unitofcurrency than hard drives."
On which planet is this? I walked into Fry's the other day and saw 80GB drives for $150. Show me where I can get even a tenth of that in RAM for the same price.
- Store only application data in your ram drive... all of this data is easily restorable (make an image of a complete install for example) and would fit in a 1-2GB RAM drive. The problem is that you have (and read) data more often than you deal with the applications themselves... so you don't gain as large a performance benefit by having your commonly accessed data on a RAM drive.
- Create an automated process that mirrors your RAM drive onto an old fassioned platter drive. Set this process to run automatically once a day at a time of low usage and you only loose a day of changes. Add an option to force sync with the hdisk and you're closer to optimal.
And of course, integrating a UPS with this (If power loss then write to disk!) would sweeten the deal.or...
Would this be workable/useful??? I don't know... I think we would need even cheeper RAM to feed the market's hunger for disk space... and I shudder to think of the price on 100GB of RAM (even at today's prices).
If I can't see it in Lynx I'm not interested.
Back in the day, I used to run Doom from a ramdisk on my 486, since I had worked a configuration that supported 16MB simms on my motherboard.
Perhaps this would be a good way of utilizing the speed of the current RAM technologies to increase the speed of one's computer. Much like technology has created a single purpose bus for graphics (AGP) perhaps a single purpose bus for RAMDisk usage could be made as well. Thus creating a place to store (perhaps only temporarily) the binary and datafiles that your system uses like a cache...read once from disk at boot then read from ramdisk forever more. Write the changes to the cache back to disk when the system is shutdown. This sacrifices startup/shutdown times for inline performance. Another thought comes to mind about the way we use databases to track the usage of our MP3s and other such things, this kind of thought could be applied to determine what initially gets loaded into the ramdisk, for instance.
Of course there are flaws in what I've concieved here, but I'm not an engineer, I'm a lowly *nix and windows luser/admin.
Hell, put gcc and the libraries and header files on it - building a kernel would fly.
All you people who keep talking about power loss, think rechargeable battery...
Just incase you didn't know. Take a look before you post, just peruse it. I mean how man posts of "What happens if the power goes out" can one have? I mean really?
i have been very pleased with my sandisk flashdrives. basically they are IDE-interface drives with flash memory instead of spinning platters. 0 ms seek time is nice, so is -silent- and -very very low power- storage. not to mention if you don't have to treat it like an egg.
i've used both the flashdrive from sandisk, and the IDE flash drives from simpletech.
the sandisk flashdrives have sizes from very small (4 MB) to big enough for your MP3s (2 GB). of course they get expensive at the high end :) best things about them are (1) can get them semi-cheap from ebay and (2) standard IDE interface.
-samThe REAL sam_at_caveman_dot_org is user ID 13833.
I think that /. readers would do well to think about this topic and its larger implications. These guys post something totally moronic, and they don't pull it down or correct it.
This is not a site with a lot of editorial integrity. It's a fun site to read, it's a fun place to post, but it's not a place to go if you want facts you can count on.
Secondly, STFU with this "most boards won't support more than 2GB" bullshit. Yeah, sure, on your lame little x86 box. You can easily find 4GB x86 server boards, and this is assuming that you want to confine yourself to such a lame architecture. With the release of StarCat, Sun E10Ks will be dropping in price soon, and you can put 64GB of memory in those babies. Of course, with cheap 64GB IDE drives becoming more common and 64GB SCSI drives (i.e. real hardware) can be found for the right amount of money.
This story perfectly exemplifies the shitfucked asscrap that is Slashdot today. I hate you all.
--
I like to watch.
I assume MO here means magneto-optical.
Who the hell has an MO hard drive? MO WORM drives used to be pretty popular . . .
Hm.
-Peter
The chips do take up space (they're not exactly wafer-thin once you put the memory chips on, plus the issue of the pin interconnects to the mobo) and I'd imagine that heat would become an issue if you planned to use them as a storage device.
Nice try.
Easy does it!
This comment has been submitted already, 276865 hours , 59 minutes ago. No need to try again.
The TAPR offers a card that makes a Compact Flash card act like a hard drive. Plugs right into a ATA-HD plug.CF is pretty cheap now as well.
--- http://homepage.mac.com/gregjsmith
I'll be damned if I can find anything at ATTO's website, but they used to make the SiliconDisk II, essentially a SCSI hard drive made completely of DRAM (yes, it has power outage protection).
40 gig hard drive = $80.
0.25 gig SDRAM = $20.
40 gig SDRAM = $3200.
FWIW, I considered making myself a 700 meg RAM drive for CD mastering at high speed but realized that I'd eliminate the advantage by first copying 700 megs to the "staging area". Unless I was planning to run off a hundred copies while doing some serious disk thrashing, there wasn't much of a point.
"I never quite thought I'd see this in my life time, but RAM is now cheaper when it comes to memory-per-unitofcurrency than hard drives."
Even using the cheapest RAM I could find and the most expensive HD I could find, you're still off by factor of 4:
PC100/64M = $3 -> 21.3M/$
Seagate/18.2G @ 15KRPM = $239 -> 76.2M/$
Damn. That's some sad shit when someone who thinks he's a nerd can't handle basic arithmetic.
Would that not fix the bandwidth problem of SCSI and IDE? If I'm wrong someone explain why.
I don't know who makes it, but I saw this crazy-ass RAM drive at SIGGRAPH this past Summer.
Basically it was this huge rack-mounted device with a built-in UPS and fiber-channel interface to the host machine. You could stick a TON of RAM in it--I'm not sure if it was off-the-shelf DDR RAM or what. But they had several hundred GIGS of RAM I think. The whole kit, with RAM, cost like $100k. It was amazing.
>>>
RAM is now cheaper when it comes to memory-per-unitofcurrency than hard drives.
In general, RAM is still about a 30x more expensive per megabyte than a hard disk.
512 MB DRAM costs roughly $50. 76 GB HD costs roughly $250. That puts RAM at ~0.1 $/MB and HD at 3.3x10-3 $/MB. 76 GB of RAM would cost ~$7600.
The price per meg for a solid-state HD would be worse than straight RAM since one needs the RAM, for starters, and then a controller/interface, battery, and some non-volatile storage. If the storage is flash then the price/meg just went way up. If a HD then, well, duh.
Now if there's a big break-through in inherently non-volatile memory, like dirt-cheap FRAM, then we might have something.
-Iz-
Instead of a solid state drive... I think what would be more useful might be a new PCI ATA100 controller card with a dimm slot or 4 for a nice, fast buffer. I know some SCSI/RAID controllers have been putting large caches on their cards for a while... I wonder if this idea could be applied to an ATA controller for a beneficial effect using cheap, readily available PC100, PC133, DDR, etc dimms.
Redundant Array of Inexpensive Disks
or
Redundant Array of Inexpensive DIMMs
The slashdot crew over the past few days/weeks have been extremely out to lunch, has anyone else noticed this?
/. or Salon.
/. gets over 200 story submissions per day, and yet the average number of story postings has gone way down, now to about 10/day. What's going on here?
Example 1:
but RAM is now cheaper when it comes to memory-per-unitofcurrency than hard drives -- cliff
RAM is 30-40x more expensive than HDs, I don't know WHAT he was smoking when he thought that...
Example 2:
I suspect a fair number of people never try Linux or one of the BSDs because they're moderately happy with AOL as an ISP -- timothy
how many people do you know who would be running Linux if it wasn't for the fact that they were using AOL? (Let me rephrase, how many tech savvy people are using AOL (that aren't forced to)?)
And the anti-Microsoft hysteria has been especially harsh over the past few days. That article about File Extensions And Molopolies was so pathetic it didn't even qualify as satire. It should never have seen the light of day on either
And
If God gave us curiosity
On a related note, if Tivo's were to use solid state hard drives they could ignore Pause, Inc.'s patent on pausing since they require a disk-based memory system. Or so I recall from they patent papers.
These are an example (they even have Linux drivers), but an 8GB unit is still over $20k (see CDW). It's going to be a while until this is affordable (2 orders of magnitude price reduction).
Can You Say Linux? I Knew That You Could.
I remeber that IBM developed a solid state drive a year or so back. It had the fastest seek time of any drive available at the time, but the fastest Ultra 2's had a better throughput.
Doesn't RAM still crap out too easily to be a viable alternative to the platter design of current hard drives??
Just give us a small plastic case with a circuit board and about 10 ram slots so we can go out and buy our own ram to put in it and make it as big as we want. add a small battery pack so our info dosent go away if we unplug it for a week or so. (these are probably meant to be left pluged in) make it so it can be connected through USB, Firewire even for the old computers parallel and there you go.
To get solid state hard drive they must be more desirable than platter HDs. All that solid state has going for it is speed. It's far more expensive, holds less data, and unless you get the expensive chips, looses all data when the power is turned off.
Current HD tech has HD's maxing out at 400GB. I'd perfer the robustness of solid state, but platter drives are simply better at this time.
Imagine a solid state file server though! Sigh.
Democrats or Republicans. They are both taking us to the same place and they are not afraid of us anymore.
I have been looking for a solid state disk for a long time now. These spinning hard disks are the bottleneck of modern computers :( I have a quite fast processor, lots of memory, Geforce, ...
:( Imagine installing your Windows on a bootable solid state disk -> WHEEE at last some performance with Windows!
I would be satisfied with something that would be 500-100 megs big, be a LOT faster than ordinary hdd and would be BOOTABLE. Being bootable is important. And that's when it comes hard finding such a device
I would be ready to pay something like 1000$ for such a system. With that money you could get a big hdd, but I prefer speed over anything else. You can always buy some big traditional hdd for your storage needs.
It does not have to be perfect for consumer use. It does not have to be 110% reliable, at least I am ready to install Windows again weekly. With the faster disk it would take only like 30 minutes in total with all the additional drivers and stuff.
In case anyone knows a solution in proper price range, please tell.. I will contact the sellers and get myself one for serious testing.
Rocket Drive(TM) Solid State Disk
In September 2001, Cenatek will debut the Rocket Drive(TM) SSD, the company's flagship hardware product. The Rocket Drive delivers the fastest access times of any storage device available. Utilizing standard Dynamic Random Access Memory (DRAM), the Rocket Drive achieves its price/performance advantages through use of an innovative PCI bus-attached form factor that is vastly different than conventional, channel-attached SSD devices.
of course i don't remember how, as my dad was the one doing it and i wasn't old enough to remember what he did. It's not necesarily a new idea(using ram as disk space, the ram hds are something relatively new), it's just become slightly more feasible than it was when i was a kid.
Got Freedom?
Thinking?
A friend of mine and I had been discussing this EXACT concept a few mos ago.. It doesn't seem like it would really be that hard to implement assuming the power requirements for refreshing the ram weren't too high..
:)
:) I actually used to run one of my macs off a RAM disk.. I just set aside like 128mb for the OS (*sigh*.. remember when OSes took up less than a gig of install space? Or fit on to a fuxing floppy for that matter.), and it'd boot in about 1/10th the normal time. I could crash and reboot and whatnot and the data was fine.. Only thing that killed it was if I turned off the power.
:)
Power wise, it seems like you could just mount a nicad battery on whatever was holding the ram and just have it recharge while the system was powered on. That way you'd get a pretty decent life I'd think.
But someone else brought up something my friend and I hadn't thought of when we were discussing.. The issue with the speed of the bus being the limiting factor.. I wonder if you used like an Ultra2 scsi controller if then you could maybe hit the "theoretical" 80mb/s rate rather than what you usually see of being more in the 4-10mb/sec range? Still probably not as fast as if you could somehow have it tie in with the real ram, but better than a normal hd.
There has to be some way to do it though.. Maybe new motherboard manufacturers will start adding in extra DIMM slots for ram disk.. Definitely nice to be able to have a 2gb ram disk you could store your os partition on.
Back on track.. This definitely wouldn't be something you'd want to store your 40gb mp3 collection on, but it'd be nice to leave things on that you needed uberfast access to.. i.e. OS files, imaging/video scrap and project files, etc..
Just thought I'd add in my $.02 since I already had this discussion w/ a friend.
It's obvious: Osama has taken control of slashdot and is slowly warping our minds into believing non-sensical FUD! We'll soon be marching off to the virgin filled afterlife of suicidal death!
Their pricing seems a bit steep for what you get. Why is the cost so high?
There are two ways you can do this.
Way 1 -- Use a PCI card with 4GB of RAM on it as primary storage. At the end of the day, or week, or whatever, copy all of the data to more "permanent" storage. Like hard disks. This way a power loss (or battery failure) isn't too much of a nightmare.
The drawbacks are that you need special hardware and you could lose days of work.
Way 2 -- Cram your machine with as much RAM as possible. Which probably means 4GB. Configure your OS so that it uses about 95% of RAM as a buffer-cache.
Data will be loaded from disk initially on demand (which means slow startup) but will almost always stay memory resident thereafter. The OS will also commit dirty pages back to disk from time to time ensuring that you don't lose anything important.
This may be less doable with systems that insist on synchronous writes during file operations, but you can often disable these things if you want to take the risk.
The benefit of this approach is that you don't need special hardware and you're less likely to lose data than Way 1. Which basically means you can and have been experiencing this now.
If your system grinds disk consistently after several hours of use, it's a good indication that you should get more RAM considering how cheap it is.
I seem to remember that there was a company working on the idea about 2 years ago of using the rewritable film of a CD-RW as memory.
- - - If the sun is a star, why can't I see it at night?
Hardware:
/.ers do... So my computer takes 1.3 more min to boot, that' just a little more time savoring the cup of coffee I bummed from the guy down the hall.
What about things like flash ROM, like they use in BIOSes? How many times can they be flashed? How long does the data last?
OS:
Shouldn't the entire OS and several apps be able to fit in to 512MB of RAM? Sounds like this is a question of transparent preloading, or optimizing paging for the application use that
We understand the concept of the battery, smartass.
We need a UPS instead. And the "u" part is the tough part.
-Kasreyn
Kasreyn: Cheerfully playing the part of Devil's Advocate to hairtrigger
IBM DeskStar 75GB EIDE ATA/100: $269.95 @ Microwarehouse
128 MB PC100 ECC DIMM $39.95 @ Microwarehouse.
So, doing simple math, this would make a 75 GB memory hard drive only $23,408..
Am I missing something here?
--
$ chown -R us:us yourbase
Jeesh... They are just getting into 8 meg caches on IDE drives. WTF? Why wouldn't they start locading these things up? Are margins *that* thin?
Life is the leading cause of death in America.
Sure these are not cheaper by the MB, but they are incredibly cool!!
Co-founder and designer at Music Nearby: http://musicnearby.com
why do you really want this solid state drives? why not just have the OS pre-cache as much disk as it can.
I usually don't hear a peep from the hard drive when I start netscape under linux (though that's after having it started & quit once already -- 12 hours earlier!).
The last CompactFlash card I bought for my digital camera was well under $1/MB (actually about $0.67/MB).
The first SCSI hard disk I bought for my Mac Plus was over $10/MB, and held less than 1/4 the capacity of that CF card. And it weighed 14 lb.
Flash isn't cheaper than current technology disks, certainly; for the price of a 1/4 GB CF card you can get an 80GB IDE drive. But the growth of the digital camera and PDA markets has driven the cost/MB of flash down, and will continue to do so.
What would be cool is a RAID controller for CompactFlash; plug in 6 CF cards in a space the size of a standard hard drive and have it do RAID-5 in hardware. Slower than stock RAM, but non-volatile. The catch there is the number of read/write cycles...and I'm not sure how much work has been done on improving that side of flashRAM performance.
When I worked for a large toy retailer we used tons of DEC hardware and we built systems in 1998 with DEC solid state 4G SCSI attached drives.
I seem to remember the required a lot of maintenance.
It would seem to me a 1 or 2 gig PCI card or IDE interface memory drive (or even better, a system built into the motherboard) that was bootable could offer a huge advantage even to those who use 10s of gigs of HD. I would think just having the entire operating system and all the DLLs etc. in such a fast device would improve performance. With two gigs or three gigs you could store your most frequently used program files on it and just store all your MP3s, pics, vids on your 'old' platter drive. I think the ideal would be a motherboard that offered a special ram slot (or two) that accepted 1gig memory modules of some sort and treated it as a drive would be sweet. The motherboard would have to take care of the power concerns but....
Oh, wait.. why am I recalling the joke about a solar powered flashlight?
Escher was the first MC and Giger invented the HR department.
...for quite some time. Still, as others have pointed out it's still not the cheap solution. But if you need fast access to data, it is really neat. I have no affiliation with SolidData but I worked for a company that had their equipment. Well thought out design. The units had their own UPS and a regular hard drive inside the case. In the event of a power failure the entire contents of the RAM disk was copied to the hard drive before the unit shut down. Likewise, when it would power up it had to copy the contents of the hard disk back to RAM before it was available. Other than that, as far as the OS was concerned, it acted just like another hard disk.
"The avalanch has already started, it is too late for the pebbles to vote." -Kosh
I'll give you everything else, but :
how many people do you know who would be running Linux if it wasn't for the fact that they were using AOL? (Let me rephrase, how many tech savvy people are using AOL (that aren't forced to)?)
That's sort of the point he was making. Poorly, but still... If people weren't "forced" to use AOL, they'd be in Linux.
IBM is developing what is called MRAM. It doesn't lose it's data when the poer goes out
e mo ry/newmemory.shtm
http://www.cuttingtheedge.com/qtakes/2001/new_m
when you run out of power, you lose it all... unless you're dealing with something like Flash-RAM or Flash-ROM, but those would wear out quick with constant flashes to add and remove software, and as I understand, with large data, they'd be slow...
bear in mind, this is based on my limited knowledge of hardware...
Diji
"I came, I saw, I WTF'd!"
If we are going to use RAM for storage, why even bother with SCSI and IDE? Why not start from scratch by inventing a PCI card that doesn't need to communicate through any bottlenecks like existing HD communication standards?
Maybe it is just me, but why don't you people use GNU/Linux and compile in tmpfs support. It IS a RAM disk, but you have a lot of flexibility with it and speed. Not to mention, forget the downtime issues when you have a *nix at yourside :) Load up your PC with 2 gig of RAM and you are set.
of course, a system crash or a reboot would do about the same thing.
This by itself would would preclude many script kiddies using notoriously unstable OSen, never mind systems that get infected by trojens etc.
"issue the reboot command now!"
heh
"It is a greater offense to steal men's labor, than their clothes"
If you're updating the platters in the background, then you're using the memory as a write-behind cache.
Now explain to me how this is different from using main memory as a VM cache in unix?
Ben "You have your mind on computers, it seems."
SSD's have been around for quite some time. Compaq had several commercial offerings based on Quantum's SSD. There are also several no-name companies that manufacture solid state drives (Memtech being just one: http://www.memtech.com/Prodinfo.htm).
We actually got our Alpha vendor to let us try an SSD for 30 days. The drive was fast, but we found that we quickly saturated the controller (something a couple U160 drives can easily do). In that regard, it wasn't that fast at all.
And, as has been said in other posts, it's not really economically fesible. We tested a 3.2GB SSD last Christmas that cost $25,000. For that application, we thought it was a good fit. But if you're concerned about capacity, we just bought some 180GB drives for our SAN for about $5,000.00 each.
While the RAM and disk capacity available now is amazing, I don't think we'll ever see the dollar/cost ratio for RAM beat the dollar/cost ratio for disks.
In 1994, which I had a 486/DX2 66 (which came with 4MB Ram), I bought 16MB of RAM for $560.00. Quake was 15MB, so I could load it into a ram drive and play from there. Guess what? It wasn't noticably faster than my IDE hard drive, but Windows screamed. =)
"All I ever wanted was to see Larry Wall give Bill Gates a Perl necklace."
http://www.eisenschmidt.org/jweisen
No offense, but could an editor please fix this? I'm almost embarrased to say I frequent the site at this point.
Yes, RAM is cheap, but unless you regularly swipe sticks of it from factories in Asia, its *not* cheaper in memory-per-unit-of-currency.
Sometimes I wonder if the /. editors even frequent Pricewatch like the rest of us. Here's an example:
$3 for 64 meg is the cheapest memory-per-unit-of-currency on RAM
That's 64 meg/3$ = 21.333 meg for a buck. Remember this is the *best* memory/currency ratio for RAM on Pricewatch. (And thus the world)
$199 for 25.0 gig is the most costly memory-per-unit-of-currency on Hard Drives. /$199 = 125 meg for a buck. Remember this is the *worst* memory/currency ratio for HDs on Pricewatch (And quite possible, with *that* high of a cost for a measly 25 gigs, the world. Do *not* take up that deal.)
That's 25,0000 meg
So yes, at this point I'm embarrased to see that above comment by the editor.
That means usable chunks. A 256MB Ram stick is $20. You can't buy a new hard disk for $20. That's the point. If you don't need a 30GB drive for $100, you don't have the CHOICE of buying a (new) one for $20 at 6GB.
Think about it, you could put your X/KDE/Gnome/netscape/Mozilla and Open office on a $20 stick of ram for nice fast response. A windows swap file on ram would be faster too - unlike Linux which swaps well on its own already - thus not needing the ram drive.
There is a company in Sweden developing technology that might make both RAM and HDD's obsolete.
:-):
6 01 2
:-)
;)
The swedish R&D site:
http://www.thinfilm.se/
The norwegian mothercompany:
http://www.opticomasa.com/
Article about it (in Swedish however
http://www.nyteknik.se/pub/pub26_3.asp?art_id=1
More material can be found by searching for Opticom, Plastic memory,thinfilm etc..
Interfaces should not be a big bootleneck. Whatever technology used to create the RAM disc. ATA-100 (100MB/s) and SCSI U160 (320MB/s) should be significant. U320 and U640 will come within years.
If the current number of RAM sockets are a limit.. one can always network some MB's stuffed with RAM.
pbRemove(a)ludd.NospamherEluth.RemovEthisse
Anyone in need of computer consulting with unix or programming btw?
(1) ram is still an order of magnatude more expensive than disk.
(2) For business users, those presentations, documents, and spreadsheets are numerous and large. For a lot of Slashdotters, those MP3's and jpg's are numerous and huge. For the hardcore, multiple copies of source trees, tools, games, etc. are numerous and huge.
(3) RAM doesn't scale nearly as well. 128M stick is cheap but a 1024M stick isn't. In order to get a few useful gigs of space, you'd need to use 1024M sticks.
(4) Take a class on computer architecture and learn about why caches make *so* much sense. A significant amount of the time, you're going to have locality working for you. So why not use secondary storage (disk) for what its good for -- cheap and plentiful? For Linux folk, just toss in a few more sticks of RAM in your box and you'll see almost RAM like speeds without needing to go 100% RAM based. I already see that with as little as 512M of RAM.
You see solid-state disk drives used mainly in relational database management systems as a 'scratch pad' for highly-volatile data.
:D
In order to explain I'll have to do a quick primer on RDBMS' and how they handle memory management.
As you're probably aware, there are a multitude of different operations you can perform on a RDBMS; UPDATE, DELETE, SELECT, etc.
For more efficient queries the RDBMS will cache physical data structures in memory. It may cache parts of the index or recently accessed data. If the cache is full it will kick out the oldest, least used parts to make some room for the new stuff.
To make a long story short, most servers have way more disk space than RAM. As such, it will use a designated 'temp' or scratch area for some of those sorts (and temporary tables) if there are more important things in RAM or it cannot all fit. In Sybase / MS SQL you create a special database for this called 'tempDB'. I'm sure DB2 / Oracle have similar data structures.
Here is where solid-state disks enter the picture. You can buy a small solid-state disk (9GB or less) for cheap. You then 'create' tempDB on the solid state device. That way you can completely eliminate the relatively slow disk drive for things like sorting, temp tables, etc. and devote all of your RAM to caching database information.
To me, this seems a lot better than using solid-state devices exclusively as a storage medium. Initially when you start up your RDBMS the cache is clean. After people run a couple queries the important (and most hit) indexes and data are cached any way so you do not have to worry about touching the disk unless you perform a write. However in most OLTP (online transaction processing; a la web app) it's mostly selects so you wouldn't receive the benefit of the solid-state device unless it wasn't in the cache.
Most SSDD have a battery-backup in them in case of power failure and are generally mated to a corresponding hard drive. When the SSDD is idle it will flush the writes to the HD to keep the HD up-to-date. On a power failure it will immediately dump changed data to the HD (also battery-powered).
For 'home' systems I can't imagine anyone using SSDD as their primary storage. It doesn't make sense - rarely does anyone perform anything that 'demanding' as to require solid-state drives. Plus, if you have a single memory error you would lose the entire thing (break one of your DIMMs and tell me what happens when you try and boot.)
Thanks,
--
Matt
Sixty bucks will get you tens of gigabytes of storage in a hard drive, but well under a gigabyte of storage in terms of RAM. Maybe you can get a lot of crappy offshore SDRAM for sixty bucks, but even so, it still isn't even a tenth as much as the same money will get you in terms of hard drive storage.
A disk array with a big front-end RAM cache effectively gives you RAM-like access speeds for cache hits. You can basically adjust the amount of cache to get as close as you want to RAM speed overall for your workload, while also taking advantage of rotating media's price and durability advantages. Ideally, either the cache is either battery backed or the array has enough of an internal power reserve to dump cache to disk even when external power is lost. This use of a large but safe RAM cache is the main thing that differentiates a Symmetrix or a Shark or a Lightning from some low-end POS that's really no more than a stack of disks with a plain old PC bolted on the front...and don't even get me started on the abomination that is host-based RAID.
Slashdot - News for Herds. Stuff that Splatters.
Is the low price these days due to more efficient manufacturing or market saturation? If it's an efficiency thing then it might make sense to put the effort into doing solid state drives now. But if this a transient glut in the market, then by the time you have something that will do the job, memory may be prohibitively expensive.
Personally I'm thinking just packing my system full of memory would be the best solution. As others have mentioned, an OS with good disk caching built in can be as good if not better than a RAM disk. It might be useful to have some way to expand memory through a PCI slot but it seems like, for now, solid state storage just isn't worth it.
This sig has been temporarily disconnected or is no longer in service
As in a Peso is cheaper than a dollar - even a Canadian dollar :p
You can buy a 256MB stck of ram for $20. The cheapest new hard disk is 30GB at about $100 at CompUSA, etc.
You can NOT buy a 6GB hard drive or a 256mb one for $20. That's the point.
He could have said "a usable amount of ram is cheaper than any new drive you could buy today to do the SAME job."
The job is of course, to hold X, Netscpae/Mozilla, OpenOffice, KDE/GNOME and gpp on a fast drive.
in an attempt to make a homebrew solid state solution a month ago, i purchased 2gb of pc133 and threw it in my desktop.. only to discover that a limitation in the linux ramdisk code (malloc issues i believe) limits the size of ramdisks to 512m, and even at that size i experienced some incredibly flakey behavior.. not to mention the fact that enabling large memory support in my kernel broke the nvidia glx drivers and a whole bunch of other stuff that was very obviously never tested on a machine with crazy amounts of ram.
using a combination of a huge initrd image that never unloads, and a journaling filesystem like reiser it would be incredibly simple to build a machine running entirely from solidstate media using a network/platter-based volume to re-populate the ram on boot in the event of a power loss to the last mirrored state of the FS..
but the code is lacking! *nudge nudge*
-hmodes
How about an array of Compact Flash cards similar to RAID?
Part of the reason RAM prices keep dropping is the supply/demand effect. If there's suddenly a new use/market for RAM then new demands would be placed upon the supply. Who knows where the price would equilibrate at.
Widespread use of solid state drives seems unlikely (near term) to me.
From western-digital.com I can get a 40GB 7200RPM UATA/100 caviar harddrive for $117.00. That's 341.88MB per dollar.
Funny, from western-digital.com all I can get is "agency natasha digital cyber friends online catalog of russian women. dating.servicelivenow- online personals and profiles. arabic dating digital cyber friends for mostly middle eastern men and women to place ads. romantics network digital cyber friends features a directory of matchmaking sites, free chat, postcards, advice, backgroundsets, ideas, and more."
Add a ram drive in software, point your /tmp to it.
Centek has a $25 ram drive sw for $25 for windows
ramdisk.
Just load your programs into ramdisk.
Have the data that needs saving tossed onto the hard drive periodically by a script that dumps the data that needs to be saved from a ramdisk directory, to a HDD.
The Kruger Dunning explains most post on
see:
6 32 2,00.html for a full review. $14,000 for 4GB is a bit steep, though.
http://www.zdnet.com/sp/stories/issue/0,4537,39
It also has a battery-backed up disk image of the ram-disk (if that makes any sense).
If you never reboot your system and the power never goes off you've got nothing to worry about... and my power usually doesn't go off... oh crap... nevermind...
(Oh yeah, RAM disks, cool. etc.)
sulli
RTFJ.
Buy all the memory your motherboard can handle. If ~2GB is not enough for you, buy a better motherboard. Then run Linux, and it will cache everything you use from your hard drive in all that ram and you will never hear your hard drive spin again (or at least until you reboot). This is a MUCH better solution than hacking together some kind of solid state ram-drive with a UPS and weird new IDE interface just to get a tiny improvement in throughput.
I just put 2 100 GB magnetic disks drives into my TiVo.
I think 200 of the 1 GB SDRAMs would take up quite a bit more space, even if the slots were there.
"Provided by the management for your protection."
Well since its stored in RAM, and since i love reinstalling my OS regullarly, why not the rest of my data, o wait, I cant as its been lost due to erm, lack of persistance?
Come on, in RAM? this has gotta be a joke, we need a real storage system, one that STORES the data:)
----- Whats wrong with this picture? http://www.revoh.org:1234/whatswrong
Platypus Technology
http://platypustechnology.com
"Platypus Technology has designed a range of storage innovations that free applications from the bottlenecks caused by hard drives.
You can run mission critical files from silicon, rather from rotating platters".
The design appears to be quite nice.
The price appears to be outrageous.
From www.cdw.com
"Platypus QikDRIVE8 1GB
1GB PCI solid state hard drive card for PC and Mac workstations and servers $3229."
Dave Barnes 5 breweries within 6 blocks of my house
Cool idea, but a small amount of storage (up to 256 MB) compared to mainstream hard drives:
http://www.sonnettech.com/product/piccolo.html
To-do List: Receive telemarketing call during a tornado warning. Check.
The price of RAM is still 30x more than hard disk space, but if Moore's law continues, it will eventually be cheaper. I am eagerly looking forward to this day since I believe it result in some incredible changes in OS and Application design. Those of that have been around a while will remember the day when hard disks finally became affordable. Improved access speeds and larger storage size allowed all sorts of new applications to appear. Consider how pervasive SQL databases are, yet we would not have all the applications associated with them without affordable hard disk technology. I think the transition from hard disk based systems to memory based systems will create many opportunities in the high tech world.
Chris Hafey
The sheer physical layout size of a bank of DIMMs that large presents tremendous routing problems. You need to match the trace lengths while keeping the longest traces within a certain limit; having slots so far apart makes that very hard.
I don't think so:
Cheap RAM: $CDN 39.68 / 256MB PC133 CL3
Or roughly 15.5 cents per megabyte. At those prices, a 40GB hard disk would cost over $6000.
It's called math, people. It's not hard. You should try it sometime.
Twoflower
--
Twoflower
With this trend to continue, OSs should be redesigned. The hard disk has the advantage of keeping the data with no power, but the ram has speed. New pcs could have 3GB of ram and a 40GB ide HD for storage. When the pc boots it would copy the data into its ram and then execute all programs from ram, sure this would take a long boot but with new os to be stable this should not be a problem.
We would have to do some serius os and user interface redesign. If the pc is used for video editing the samples could be kept in memory this would speed thing up a bit, but you would have to save the data to the HD eventualy.
Another great application for this would be chase servers, imagin a organization that does video editing and all the clients have gigabit ethernet, implement servers that have 1TB of ram before the data storage server at night they could sync the data.
Seriusly, we have to think about this, our current view on pc is that ram is way more that hd storage. Diskless clients could make a come back...
hmm... for fun I enjoy launching DDoS attacks against 127.87.42.5
As such, they are fairly old technology, and most of the problems have been ironed out. The problem with power can be solved in a number of ways, for example. You can have battery-backed RAM, or you can have the "RAM" non-volatile by using a design that does not decay rapidly with time. (Flash RAM works this way.)
Another problem has been the capacity of a solid-state hard-drive. This, as has been mentioned, has largely been overcome. I =STILL= believe that wafer-scale chips are the way to go, for this, though. You should be able to make wafers that are tens of terrabytes in capacity, by now.
(The problem with making wafers has always been the purity and the defect levels. Purity just requires you to use something better than skimming. Double distillation, or atomic mass seperation, would give you near 100% purity. You then just cool the resultant in a vaccuum flask, so that the defect rate is negligable.)
Getting back to the modern day, though - how to turn cheap RAM into quality solidisk. This involves making a card, with a whole load of RAM on it. Since you're using conventional RAM, you can't rely on modern-day core memory. This means the fall-back of using battery-backed RAM.
You want TWO batteries, for this. One will be in discharge/recharge mode, the other will be in operational mode. When the batteries switch over, you want the recharged one to be switched first, so that the batteries are in parallel, BEFORE switching over the other. That way, there's no loss of power.
When switching to discharge/recharge mode, the battery must be fully drained, to prevent "memory", where a rechargable battery fails to recharge correctly from a semi-charged state. Once drained, you recharge it to capacity.
The switch-over should happen on one of two events:
This guarantees that you have 175% - 200% of any one battery's lifetime, which should be ample for most purposes. The recharger should tap off the bus' power supply, with the batteries directly powering the RAM at all times. This avoids any problems of messy spikes somehow getting into the computer.
If you want "extra-long-life" SSD technology, you are probably best off using very low-power RAM for the main disk, and using higher-power fast RAM for the cache. The lower the power of the main disk, the better. Static RAM is worth a glance, for this - I think it's usually more efficient than dynamic.
Of course, the =ULTIMATE= solution is to go back to using core memory. (For those who never went to computer science classes, "core memory" is one of the earliest non-volatile digital storage systems. It was a form of magnetic storage, and used semi-permanent magnets to retain the data. Data could only be read by destroying the copy in storage, which mean that a read cycle also had a write cycle. It was slow, but when you had RAM that was guaranteed to retain data for over a century, who cared?)
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
2. This bus could be HyperTransport from the NB to a HyperTransport enabled memory controller that can control up to 16GB of memory. This will give you massive bandwidth and low latency - the best of all worlds.
3. 16 DIMM slots in a drive bay somewhere, or whatever. connect to the memory controller. Battery connected to power DIMMs in case of power down. Use DDR DIMMs, as they use less power. A large laptop battery should power 16 DIMMs for well over a day on their own.
Alternatively, just set up a massive RAM drive and cache the HD into it... rewards uptimes of course!
- Ram is so expensive that having it sit idle is a waste of money and time.
- Operating systems do an excellent job of keeping most recently used (and hence most likely to be used again) data in memory
- Keeping files on a ram disk prevents the operating system from using it
To learn this initially, I took a machine with 512mb of ram and made a 100mb ram disk partition on Win2k. I needed to speed up my compile times (>45 minutes) when using a bad cross compiler to the Nintendo Game Cube and a lot of templated C++ code (I didn't write it). After moving all the source code and object output files and executables to the ram disk volume, it turned out that it went even slower than before. This is because less ram was available, so it swapped out more frequently. Same principle applies when just adding more ram. The less you hit the hard drive, the faster your machine runs.The only reasonable purpose I can think of for a fast ram disk is if you can get some relatively slow ram on that device, which is cheap, but won't fit on your motherboard due to it requiring faster/more expensive ram, such as RDRAM or other exotica like ECC Registered SDRAM. But it's still cheaper to get a few hard drives.
Any connection between your reality and mine is purely coincidental.
I see some people debating ram disks.
The way I see it, the kernel is smart enough to use ram for buffering when it can - certainly smarter than a user creating a ram disk.
If you need more performance, give your system more ram and let the kernel decide how much of that ram should go to a ram disk.
A family of high performance, single-chip flash disks are available in a wide range of capacities from M-systems.
I'm listening to ideas about a pci card with ram sticks on it that backs up onto a harddrive in the event of power failure. Why the hell don't we just buy a whole ton of ram, make a ramdisk that's sync'd with a harddrive partition, so all the writes are written to a disk buffer and the ram while all the reads only access the ram. If we crank up the size of the write buffer, we've got some pretty impressive performance!
Texas Memory systems makes a solid state box that provides great access times (particularly random reads/writes). This type of technology has also been used on the mainframe before for things like transaction logs and indices. This type of technology was stopped since big disk vendors (IBM, EMC, Hitachi) made intelligent disk subsystems that essentially had massive amounts of memory, internal to the disk subsystem. Now, its coming back for SAN's since people are looking at JBODS, simpler RAID systems, etc.
Everytime another advance brings things closer to "RAM-speed mass storage", it makes me wonder how operating system philosophy is going to have to adapt. If the text of ls(1) is already somewhere just as fast as RAM, why not allocate it's stack and other run-time pages from another chunk of memory and execute the code where it lies? Now as the line continues to blur... what does ls(1) print out when it runs?
Anyone out there with an HP48? That's the only example I can think of off the top of my head that was designed in that direction... store a variable or a program, free memory decreases, there's only one pool to draw from.
Are they any other examples? Is it worth pursuing, or is run-time memory technology always going to be far enough ahead to warrant moving things back and forth to permanent storage?
if I had a regular pc, and a server appliance with lots of ram with my filesystem all ready to go (backed up to a regular hard disk on the server), and I use network boot and mount the "ramdisk NFS share", how for from internal ram speeds would I be?
"The Most Fun Possible on 4 wheels" is at SunBuggy in Las Vegas
Superparamagnetisim is when ambient energy is equal to or exceeds the magnetic energy of an object. In hard drives, it is estimated that the superparamagnetisim barrier is 150GB per Sq Inch. We are not at this level yet, but once we are (est 3 years time) we will no longer be able to increase HDD size (at least in the current 3.5" format) so we will need to either investigate other technologies (like solid state.) OR we will see the return of giant platters, disk farms, jbod's, etc. like the old mainframe days.
Utilizing superconductive material to utilize the 3rd (z) plane magnetically between platters is also a possibility.
Jesse Wolfe Sr. Manager Systems Integration
Well, RAM isn't quite as cheap as hard drive space yet, but I see where this is going. I guess everything you can't fit into solid state memory could be stored on a network, or the 'net. Your MP3s, apps, whatever. Yes, it would take a fast connection, but most of us are getting that anyway. Long live the Network Computer!
I was wondering the EXACT same thing, I was recently browsing the net to find if anyone did such a project for his master or just like a hobby. Or even if there was someone that actually made a home-made device (I'd even go for that).
;)
C'mon, shouldn't be too hard to tie up a buttload of 128M+ DIMMs together and plug in a ATA100 interface and some FPGA for decoding/driving the memory? How come nobody did it? what are the big problems? I don't see any problems from my perspective it's just a load of addressing issues and plugging off the shelf parts together, the only "hard" part I could see is the timing to get the maximum throughput to max out the interface, but that's only a software issue.
Heck someone that really wants could make the first low-cost IDE (or SCSI) board/case/adapter to which we would simply have to add ram... I'd pay a lot more than what the components are costing to get my hands on something scalable and cheap like that, and I am sure I'm not the only one.
Just imagine something like.
Model-1, 4 slots, accepts up to 1GB PC133 ram per slots, ATA/100 interface 1000$ (look at the price of the components for that kind of stuff and you EASILY beat the 3x the cost of the hardware to break a profit, even home-made you could make a LOT of money (and still beating the 300% law)
Model-2, 8 Slots, blabla 2000$
Model-2 Pro, Ultra160/320 interface 2500$
Model-3, loads of slots, still WAY cheaper than the current available solutions, error correction, etc etc.
Nice buisness plan eh? copy it, make a device and send me model 2 pro
--- Metamoderating abusive downgraders since my 300th post.
This is exactly what AGP was designed for -- high-bandwidth I/O to main memory, without blocking the PCI bus. Plus, the AGP GART can do most of the address translation you would need. All modern PC (and even Apple) chipsets have an AGP interface, which is wasted on a headless server. . . until now. AGP even provdes extra power (even the obscene AGP PRO), so that an onboard battery/HDD could be used to backup.
> To take advantage of RAMdisks, you pretty much need to have your computer on all the time, or in standby mode when you're not using it.
This is true. *or* you could have your computer net-boot from a a server with one of these. Even 100megabit transferring from memory will feel faster than a local hard disk. And gigabit over copper is becoming very affordabl these days.
Those characters are underscores, not underlines, and obviously, you don't understand sarcasm, but try not to get your underwear in a bunch...
Man, look at the seeming *hundreds* of simulposts. Seems like 90% of the replies to this were either:
A) "This will never work, RAM is dynamic and requires a constant charge to retain its data"
B) "They got the math wrong, RAM is much more expensive than hard drive space!"
Sheesh!
What would be great would be a cheap backplane card that plugged into either an IDE or SCSI bus, on which you could mount zillions of old 4 meg 72-pin simms which are now obsolete.
I probably have a gig's worth of 4 and 8 meg 72-pin simms sitting around in my lab with no use other than collecting dust. It would be great if I could slap them into a device to use as fast storage. I guess the RAM companies would rather have us throw these old chips away and spend money on new RAM.
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
Most modern operating systems have an advanced file cache. If you think of your disk cache as a dynamic RAM drive, you're getting the idea. A dedicated file server will serve commonly used files at RAM drive speeds due to the file data already located in the server's RAM.
Let's analyze the options.
2GB Network RAM Drive
Pros: None
Cons: Very expensive for the storage while bound by network bandwidth. No advantages over a harddrive-based network drive with a healthy RAM cache. Data is volitile -- needs constant power.
2GB RAM Drive
Pros: Very fast access for non-sequential access
Cons: Performance bound by IDE/SCSI bus. Low total storage when compared to hard drives. Data is volitile -- needs constant power.
40GB Hard Drive + 2GB RAM
Pros: Just about as fast as dedicated RAM drive access for most data sets. Hard drives 1/10 the cost of similar RAM-only solution. Very large sizes available. RAM cache adapts to filesets used. Data is non-volitile -- does not require constant power.Cons: Not as glamourous.
Conclusion: Unless you have nothing better to do or have a specific need (space or vibration-resistance?), hard drives backed with a RAM cache win.
- I don't need to go outside, my CRT tan'll do me just fine.
I can see that the RAM drive would be a cool idea (I would love to brag that my machine runs w/o HD-which would only be possible w/Linux;) ) but I think we're overlooking something just as important as cost or performance...space. Specificly, how much room would this beast take up? Well, rounding here and there, I figure that the average 168 pin RAM Mod is about 4 in long and about 1 in tall and about .125 in wide and taking into account .125 gap between Modules (for heat and install) a 25 gig RAM drive would take up 37.25 in length and be 4" tall ( that's figuring 256MB simms and not acounting for connection,etc.). IF you had a 'card' that distributed the RAM across both sides, it would be still over 18" long and over 8" in girth! Broken into 4s envision a box 9x9x3.
One question: what kind of power would this kinda thing take?
Never trust a bald barber; he has no respect for your hair
I agree - even a SDRAM controller right on the PCI bus can't be as fast as the system's main memory.
Linux, FreeBSD, and MacOSX (I dunno about Windows) all have excellent VM and file system caches (sometimes they're tightly integrated). If you have 4GB of RAM in your system, and your running processes have 64MB resident, then it's like having a 3.94GB RAM disk. That is, of course, unless you routinely access more than 3.94GB of files.
This is why having lots of RAM is good, even if your processes don't use much.
It's not prefect - I know that on FreeBSD 4, for example, if you have zillions of small frequently used files in the cache, and then you do a big tar, all those important little files will get pushed out of the cache in favor of the new file, which might only be accessed once. Also, the kernel will swap processes out to make room for file system cache, and there aren't a lot of knobs for tuning all of this. EG I don't think you tell the kernel "keep *all* my processes resident, even if they're idle... no really, I *do* have enough RAM!"
Anyway I just don't see any use for standalone RAM disks. There are very few real-world applications that need *deterministic* 1ms seek times. If you rely on the OS you will generally get the best performance.
"I never quite thought I'd see this in my life time, but RAM is now cheaper when it comes to memory-per-unitofcurrency than hard drives. "
256MB pc-100 dimms are like $20. That's $80/GB.
That's $6,400 for 80GB of memory.
An 80GB hard drive is about $250....
So what the heck are you talking about?
Per unit of currency means simply Number of bytes per (dollar or peso or escudo or lira or rupee or colone or peseta or pound)
What do you mean talking about MB for one and GB for another.. that makes no sense.. and would be meaningless.
Cliffy's just wrong.
I've been researching something like this in the past few weeks because I'm working on a.... project that will require a fast boot and needs to take some abuse, so a RAM drive sounded good (no moving parts). What I found was an IDE adapter for a CompactFlash card. OK, so you can only get max what...512M? Thats good enough for my purposes, not so good as a primary drive on my home machine. The best part (for me anyway) is that the adapter is $17, and one can aquire a card for (I think I found) $60? HERE is a link to the one I found. Scroll down to find the CompactFlash Adapters
Am I Over-Moderating??
I don't really think that was the point he was trying to make. He was, (from what I read of the story) trying to say that people would automatically switch to Linux because AOL is on it..
but look at this, AOL started on the GeoWorks Operating Environment (which ran on DOS)... is everyone that uses AOL using that? I don't think so. Why would it be any different for linux?
It's called 'disk caching'. Linux does it. Windows even does it. Everyone does it these days.
And maintaing power to all that RAM indefinitely is....... surprise, what a UPS is for.
I maybe pointless to have faster HDs in a home computer, but this is not the only kind of computers in the world. That's why RAIDs exist and why nobody uses them at home.
You really need faster drives when it comes to database storage. This is usually done with network RAIDs, but RAM could be a good replacement in some applications.
But still a bit pricey, see prices for MegaRam solid state disks. Guess the drop in RAM hasn't quite filtered through to these guys yet.
Well, the fact is that you're not talking about RAM, unless NVRAM. What you're talking about is basically some sort of flash memory/EEPROM or something, and the bottom line is that these things are slow!
Now don't start thinking you're the first to think of this. it's an old idea, and in fact there are already solid state drives on the market. Where I worked over the summer (Lockheed Martin) we actually used a 256MB solid state disc in a unit that stores flight information on an aircraft. The reason we used solid state was because of all the jitters/bad mechanical environment. The problem was that each 256MB disc was about $2k or so. Not cheap. However, it was fully scsi. so you could put it on your scsi bus, and it would work just like a mechanical hard drive.
But anyway, The point is that the RAM that is so cheap for us to buy, is totally volatile and so you need a completely different memory for the things you're talking about. Stuff that is either slower or a lot more expensive.
I don't think anyone has mentioned power consumption of a hypothetical ram drive yet. So, let's calculate it. SDRAM sticks typically come with 4, 8 or 16 chips on them. The chips can be of varying size, i.e. 64, 128, or 256Mb. To be conservative, let's use the 256 Mb chips in our SSD. A typical PC133 32Mx8 chip from Hynix runs at 3.3V and uses 120 mA operating current (http://www.hynix.com/datasheet/pdf/dram/(1)HY57V5 6820HT.PDF Sorry to all the EE majors, I was CS and I'm using a best guess in selecting the operating current.) Therefore, the chip uses about 0.4 Watts of power to supply 32 Megabytes of memory.
If we want a gigabyte of RAM, then we are now using 12.8 Watts of power. If we want 10 Gigabytes of RAM, then we are using 128 Watts of power. Just for comparison, a typical hard drive uses about 20 Watts of power or less depending on what mode it's in.
If you wanted a battery backup for your SSD, then you'd need quite a bit of juice to maintain data on a large sized drives for extended periods > 2 hours.
If one were to use 1Gb chips, which I think are coming soon if they aren't out already, then our 10GB SSD would require 32 Watts of power, which is more reasonable. Of course, Gigabit chips would be more expensive too.
So maybe, in terms of power, price, and size, SSD's based on RAM are still a ways away (maybe about 3-5 years).
S.
M-Systems offers offer some Flash-based "DiskOnChip" products used alot in embedded apps.
Hi All,
Check out http://www.platypus.net. They've been doing some interesting things. They claim sustained data transfer rates of between 110 and 350MB/sec. (The average sustained data transfer rate of a SCSI RAID 5 array is 40MB/sec). Probably is still pricey.
Back then, wasn't ram like $50/KB??
I recall 1MB dimms in 1992 or so costing $150
compact flash memory for digital cameras now comes in sizes up to 512mb. It's no where near as cheap as RAM, but still not bad. My first computer didn't have a hard drive and my second had a 40mb, loud, slow drive. Compared to that, a 512mb drive, under $500, and the size of a matchbook is pretty cool.
Aside from being expensive...
Flash is slow to write to.... and is limited in the number of writes. Flash wears out.
Persistent phase-change memory[1] that can be built on a CMOS production line is nearing production. Intel and others have licenced the technology. Intel expects to be selling 1/2GB devices in the not too distant future.
The physical characteristics of phase-change memory makes it look very attractive as a next generation replacement for SDRAM and Flash. The
switching time of the devices are reduced as the cell size shrinks. DRAMs, by contrast, will not scale well beyond their current size. Each DRAM memory cell require a capacitor that must be periodically refeshed. To cram more cells into the same space the capacitor must be grown using deep wells in the cell. The referenced article discusses other aspects of phase-changed devices add to the appeal of this technology.
When these inexpensive 1/2GB phase-change device hits the market the motherboard manufacturers will have a good incentive to add extended RAM sockets that are designed to use the new type of device on the motherboard. The kernel would configure a Linux RAM disk for the persistent memory of the motherboard. This arrangement will provide a very fast file system in without the bottleneck of the IDE or SCSI bus.
The downsized is that the extended RAM disk would probably only hold 4-10GB, which will be small compared to a typical 100GB drive that will be avaiable for little money by the time these devices are available. The file caching scheme used in managing the file systems will be an interesting topic of research if this type of system becomes commonplace.
[1]http://www.ovonyx.com/tech_html.html
The Flash file system, designed for flash eprom devices was run on PSION handheld devices more than 10 years ago. Version 2 of the Flash filesystem supported full read/write. Flash eproms are passive storage devices, meaning they dont need power to keep data, only power to write.
The same PSION device supported SRAM disks that worked great; they had a hearing aid battery for power backup.
Magnetic platters are non-volatile and do not require power for storage. When you turn the power off, the contents of magnetic platters stays there.
RAM ICs *are* volatile and they *do* require power for storage, when you turn the power off then you lose the contents of memory (FlashRAM is an exception, but has a finite life because read/write cycles degrades the memory). You need a battery to hold the RAM contents in the absence of power. You don't want to reinstall that OS, your apps, and restore your data because the battery drained too far while the power is turned off, do you?
I used to develop hardware and software for automated component testers for analog, digital, and memory components. One important spec of RAM ICs is the retention voltage. The RAM retention voltage is the minimum supply voltage at which the RAM will reliably hold its contents. This is important when backup battery cells are involved.
Do the math. A typical 3.3v 256MB RAM card may require 20mA of current at a retention voltage of 3.0v. 20mA is an arbitrary but *conservative* number. To get a RAM equivalent of a 10GB hard drive, you'd need 40 of those 256MB cards at 20mA each, therefore you'd need a battery system to supply 40 times 20mA equals 800mA at 3.0v. Most portable batteries, UPS excluded, when asked to supply even a quarter of that current demand will see their voltage drop to zero in less than an hour, and you're asking for that kind of power for *hours* while your PC is turned off and not in use.
We haven't even covered the support components yet. We're talking DRAM=Dynamic RAM which uses charged capacitors to store their contents and therefore has to be periodically refreshed or the caps will discharge and memory will lose their contents. Gotta power those support ICs too, so add their power demands to the battery.
The RAM that holds your BIOS settings on your motherboard is static RAM. Static RAM does not require refresh cycles and consumes less power, therefore they can operate on a single type 2232 battery cell the size of a US nickel. But static RAM doesn't offer near the density of dynamic RAM ICs. Static RAM has topped out at kilobit capacity per IC, compare that to dynamic RAMs' hundred-megabit capacity per IC.
The demand on a laptop battery is already enormous, they don't stand a chance with RAM HDs. You could pack a battery cell as large as a car battery into your desktop for RAM backup power but that's overkill. The technology to pack more power into a portable battery hasn't been invented yet, and that's the same achille's heel that is holding back electric cars.
Sorry to rain on your parade but there's a reason why these things haven't been implemented yet. Sure, I'd love a RAM HD; RAM access times are in the nanosecond range while HD access times are in the millisecond range. I'd love to see my OS and apps load 1000 times faster, but we have to wait for better batteries or for RAM ICs that consume less current.
Eternity: will that be smoking, or non-smoking? I Corinthians 6:9-10
is basically how caching works. It's already done.. it's not something new. Linux does it. Every OS does it.. even windows...
The only difference is things aren't cached until they are loaded the first time.
If your computer had 80GB of memory, you would invariably end up with most of your HD (at least, what you were using) cached.
Why not just increase the size of the onboard hard drive cache from 2 or 4 MB to 64 or 128 MB? That would be inexpensive and increase drive performance.
From personal experience with the company and its product, I would recommend against Cenatek. Hope this helps people out there who may have been even moderately considering purchasing a product of theirs.
This isn't exactly what the topic was talking about, but similar. You can set aside part of your RAM as a drive. It will have a letter, you can install programs on it, etc. If you have enough RAM this drive could be several hundred MB. Just do a search on Google for "RAM drive" and check out some of the articles written on this subject. There are deffinitely some interesting ways of speeding up your computer using a small, high speed drive like this.
The reason it is cheap is a supply and demand issue- not the cost of manufacturment, per se... Make solid-state HDDs... they will increase in price.
http://siokaos.org/
What I would like to see is a CD drive with a full 700MB read buffer. Does anyone know if such a beast exists out there?
First, unless I got the math wrong, 60GB for $102 (see pricewatch) is about 1.7 dollars / GB, whereas, PC133 is at 128M for $13 (see also pricewatch) which comes to $71 / GB so, Ram is still a *hell* of a lot more expensive. Even beyond that however, the type of main memory that you put into a PC (this include PC1xx and DDR derivatives) are all descendents of what is called *dynamic* ram. The reason for this is because if the memory is not periodically refreshed, by re-writing the current value, the data will be lost. The advantages to this are that this data will perform much *much* faster than other types. The disadvantages are: it eats a lot of power. I don't know how many people notice, but your typical memory subsystem in todays PC gets warm (or if you're running RD Ram, change that to *hot*) That means that it is eating a fair amount of power, and just how much space are you going to use up inside the drive storing batteries for a drive? If you used the entire 5.25 inch half height bay for powering a 2GB PC133 drive, the batteries would run out in less than a week unless the drive had a constant power source.
There are several other types of ram. SRAM (not SDRAM) is so called Static Ram. Static ram as it implies does not require a refresh. The performance is slower, but the lack of refresh makes the rest of the system simpler. That doesn't mean that it will retain its memory after the power is off, its just older technology than current memory.
The last kind of memory is a much better kind, and is known as NV ram. That stands for Non-Volatile memory. NVRAM retains its value even after the power is turned off. NVRAM is used in some systems to retain value without the need for a battery backup. The disadvantage is that it is extremely expensive because it requires different manufacturing technology from "normal" ram. It is also quite slow by ram standards.
There are in addition, a number of different hybrid types that employ advantages of one or more of the listed types without some of the disadvantages, but all of these types have the major disadvantage that they are expensive.
Now, a drive built with one of these hybrid types does not nesescarily have a constant access time. The reason for that is, that in order to reduce the cost, manufacturers buy scrap rams. The drive electronics then separates the ram module into "sectors" (ussually 512 bytes each) and keeps track of which of these sectors have burned out memory. This is almost identical to the way that hard drives deal with damage to the platters: bad blocks. So the drive has to translate from logical block addresses (if IDE, or the equivalent for SCSI), and figure out which actual location the data should occupy. Additionally, the data to and from the drive is cached because it does offer the same types of advantages as it would for a normal drive. The gains by cacheing a Ram drive are less significant than cacheing its equivalent platter drive, but at that price, any extra gain is worth the effort.
So, the access time is reduced, but still variable.
as for the suggestions of using Ram to make a much larger cache, its a good idea and all, but it just changes the point during the computer use that the cost hit of loading data has to occurr. You really only have two basic choices with current software: Boot time, or Program start time. Your choice, but it all comes out the same in the wash if you turn your computer off when you're not using it.
-=Geoskd
I wish I had a good sig, but all the good ones are copyrighted
Would a Ramdisk drive using USB2 or Fire Fire WIre be faster than using IDE or SCSI interface?
I'd like to see cheap RAM come out in the next few years based on pervoskite oxides. Nonvolatile memory so no need for batteries and instant on.
It is by the juice of the coffee bean that thoughts acquire speed, the teeth acquire stains. The stains become a warning
If people would please check:
http://www.pricewatch.com/
RAM prices are MUCH lower than people seem to think around here. I see 4GB for $601 today.
I've been browsing through the ideas posted here and here's what the ideal device seems to be (with my own ideas added, of course): To overcome the limitation of specific device drivers being required for RAM mounted on a PCI card, the ram would be mounted in a slanted, parrallel 5.25" IDE/RAID drive design. Within the casing, circuitry would interface with the IDE/RAID bus to emmulate an complete IDE drive. In this senario, to the system, a RAM disk is no different than a hard disk A second IDE cable would loop from the IDE-RAM drive to a redundancy unit, also 5.25". The redundancy unit. This unit is a IDE hard drive of the same capasity of the RAM drive. The platter disk drive is completely invisible to the BIOS and is only connected to the RAM drive drive for redundancy. Also in the 5.25" casing is the battery write-out unit that provides temporary power to the RAM and redundancy unit when the system is shut down (or power faliure) to dump the contents of the RAM in to the magnetic medium. The battery backup also allows the RAM to retain the data in it for extended periods without A/C power input. If the battery backup fails, the RAM drive loads the image on the magnetic medium in to RAM at boot time. Idealy though, the user will use the system frequently enough to never have the contents of the RAM lost. The end result is that the user sees programs and the OS load almost as fast as the current processor, IDE bus, and FSB can request it. I imagine that *nixs would boot at roughly the same rate, since most of the boot time is device configuration. Very little time is spent fetching data from disk during a *nix boot. However, I believe that a Windows base machine might boot in as little as 10 secs with this configuration. Some problems one might run in to is the increasing power consumption of large amounts of RAM chips (DRAM) and, also, the increasing cost of low power RAM chips (SDRAM/RDRAM/DDR)the solve the first problem.
Some uses I could think up was:
Use for a drive in a diskless workstation. (and routers/firewalls, etc)
Graphics rendering node (the massive datasets they need)
Cluster computing applications (web sites, data caches)
Your 'most accesed readonly'' files (can you say websites)
Just wish they were cheaper
make Linux, not Microsoft. sin(beast) = -0.809016994374947424102293417182819
Thats still a factor of 30!
Only since 9-11, I haven't RAM less than $100.
If you back up the solid state with a hard disk, you can dump to disk when the battery gets too low
However, if your computer dies before the backup begins, you lose data. You lose even more if you're not running an atomic filesystem such as a journaling filesystem or the Tux2 patched ext2fs. Even a UPS won't fix everything: if your kernel panics, you lose data. If the HD isn't fast enough to write all your data during the 10 minute window your UPS provides, you lose data. There's a reason why databases require fast disks even on machines with lots of RAM: they write out all transactions to assure Durability, one of the ACID properties.
Will I retire or break 10K?
Solid state drives have much lower storage capacity per $ as compared with conventional cached hard drives, have a niche in places where spinning platters cannot go for reasons of reliability, vibration or high G forces - spacecraft, aircraft, (especially fighters and flight data recorders) tanks, rockets, etc.
I used to work on military and avionics projects where conventional spinning hard drives could not be used. You wouldn't want to send a hard drive on an interplanetary mission, it would certainly be non functional by the time it got there.
Other more mundane applications for solid state memories are in digital cameras, (both still and video) and palmtop computers. They may also make sense in places such as remote seismographs where small blocks of compressed data are written to disk every few minutes, where you wouldn't want to be spinning up and down a HDD.
My rights don't need management.
okay, i'm no EE, and not much of an art student, but i drew a little diagram of how i think this could be implemented. feel free to get rich making one, but if you do, i want one! :) ...add a HEPA filter, and it'd make a great air purifier, too... :)
They also have relatively slow writes, much slower than a platter I believe...
And they are limited in the number of erase/write cycles. Flash wears out.
Which is exactly what Western Digital did with their 100 Gig caviar drive. They've taken advantage of cheap dram to pump their cache up to 8MB from the usual 2 MB. The result is their 7200 rpm drive is outrunning 10k rpm drives and is quieter as well.
More info on the Western Digital drive is available at storage review.
Psion PDAs (from the Series 3 in 1991, maybe even the Organiser/Organiser from the 80s) used solid state disks. There were two variants, the RAM-based fast (and expensive) with a battery backup, and the flash based with more capacity at a lower price. Capacities ranged from 256 KB (or perhaps 128?) up to 8 MB, and each PDA could accomodate two disks, expanding the built-in memory of only 256 KB (later 512 KB -> 2 MB) Psion's SSDs were never used by other manufacturers, and with the Series 5 (1997), Psion went for the industry standard Compact Flash instead.
Okay....this is joke right? Yeah...so the seek time would be great....but coming up in here in a few months, maybe less, is 350GB Hard Drives....for 300 bucks! I would like to see you even come close to that space with RAM. That would be hundreds of thousands of dollars for space! That is an absolute joke. The limit of HDD was suppose to be here a long time ago. With superimposing technology, the limit will be very far in the future. As of now...Maxtor and IBM can address 144 Petabytes of information on a disk thanks to the 48 bit addressing that is coming out here soon in the market. Now in terms of the physical complications with pushing bits and tracks together....Well...that is another story, but just wait and see.
But it is waffer-thin!
Although disks are dropping to a couple of bucks per hour of programming ( one hour = two gigabytes => $4 ), tape cost is also dropping ( six hours per $1 tape => $0.15 ). Tape will always be an order of magnitude cheaper.
This let's you use the current slots for memory (after all, we can put in a couple of Gs of memory into those slots.) and the bandwidth is higher than a PCI slot. latency issue is gone since it's RAM after all.
The one issue that remains is 'flushing' in the event of a powerdown. for that we could put in a daemon that gets a signal from upsd and makes a copy of it onto a hdd. on power-up the same daemon reads from the hard-disk and creates that ram-drive (or partition i should say).
no need to shell out bucks for that capability. it's already here. just a daemon that needs writing.
Isn't it possible to get an old pentium box (get a HP vectra or something since I think they can take a lot of RAM), stuff it full of ram and then make a massive ramdisk.
Then just setup an NFS server and big UPS. You might like to use gigabit ethernet too.
You may also like to write a little prog to copy all data to disk every once in a while, something along the lines of a crontab with 'cp -r' should do the trick, and the same again for when the UPS signals.
Could do this in a day, although you would do well to top a few gb and NFS might diminish seek time, but boy of boy it would be cool!
-- Mike
Nevermind that the topic of this article, while interesting, is not economically sound. I keep seeing people misusing terminology. Specifically SRAM. Yes, SRAM means static RAM. Yes SRAM is what makes up the registers and cache in your CPU.
NO SRAM does not save it's contents when you cycle the power. SRAM requires constant power to maintain it's state; it uses latched logic gates to store a bit (while DRAM uses a capacitor). In fact, when the computer is off, SRAM would require more power to save state than DRAM.
What I think would be cool are solid state "drives" using slower, cheaper RAM in the 4GB range that could be used in place of swap partitions or folders (just think how fast photoshop would run!)
Black holes are where the Matrix raised SIGFPE
1) There are already solid state drives in production.
2) These drives tend to be much much more expensive than their counterparts.
3) Cheaper versions of these drives use volatile memory that fails in a power outtage. Any extended outage past the life of your UPSs and you're screwed.
4) These drives tend to have a shorter lifespan than their counterparts. I have heard many complaints of them breaking down.
While I found the previous "5 Insightful" rather off too, one would think that in order to be "redundant" a post would actually have to have been made after other posts on the same subject. Having a post at 1:51 following several starting at 1:49 doesn't really seem to qualify for that either. So 3 people modded me up for making the same really obvious observation as 5 other people at the same time, and then three other people modded me down for making the same really obvious observation as 5 other people at the same time.
I'm starting to think that maybe Slashdot deserves to have articles that claim RAM is cheaper per MB than Hard Drives. It might even deserve to have Jon Katz as its feature writer.
The thing that bothers me more than speed is the noise of my hard drive crunching and churning.
The best thing about solid state is the lack of moving parts and the subsequent lack of noise.
I presume the lack of moving parts means an increase in reliability which also may be a huge factor for most people.
Minus the Mac users (Apple axed floppies awhile ago) how about caching floppies and zips. Don't jump the gun, start small
obviously the slashdot staff has been replaced by a beowulf cluster of monkeys
Has no one even noticed that there's also a memory CONTROLLER required. Not that it would have to be expensive in quantity, but you have to have some sort of PCI, ATAPI, SCSI, Firewire, ... -attached SDRAM controller. Something has to perform the SDRAM commands, including refresh, RAS/CAS multiplexing, byte lane control, and, I would hope, Error Checking and Correcting (ECC). ECC SDRAM (RDRAM and DDR SDRAM, too) is not so cheap (see http://www.pricewatch.com, for example).
/. at work.)
Games, however, do provide one possible justification for an enormous RAM disk (about 1 GByte). After installing the game to the RAM disk, compress the whole thing. When you want to play, uncompress that game to the RAM disk. Now, during game play, your graphics are available with minimal delay, so the game should play more smoothly. If you need to save game states, though, don't forget to recompress the RAM disk!
(I really should either remember my login, or quit reading
The CMOS has never been SRAM. SRAM does not have to be refreshed like DRAM but it WILL lose data if subjected to a sustained power loss. The CMOS these days is Flash RAM; on older machines it was some form of ROM. SRAM is used in modern systems only for CPU and memory caches. SRAM is VERY fast, whereas flash and ROM are both slower than plain old DRAM.
I have seen the future, and it is inconvenient.
A swap-file exists for the reason of supplementing physical memory ... but if you got a GB of RAM you're not lacking memory so why use a swap file?
m.mmm..myyy
Wouldn't one of these make an awesome swap partition?
/. would find my user info)
(man I wish
Digital and IBM sold Solid State Drives YEARS ago for mainframes and mini's. They were insanely expensive ($20k USD for a couple hundred megs) due to the high cost of RAM. They were primarily used for scratch area work, such as paging files for the OS, databases, etc. Some models would even work on a SCSI interface.
Agreed - we aren't there yet and I doubt that we ever will be. Platter disks are still lots more expensive than RAM. Quick check of my favorites shows PC 133 SDRAM at $.07-$.9 cents per MB and big IDE drives at $.002-$.004 per MB. That is roughly a 20X-40X spread. This is an order of magnitude improvement from the 300X or so spread mid-90's when memory was $100/MB and disk was about $350/GB.
So hybrid RAM/disk solutions are desirable. But RAM does not automatically equal performance. I had an interesting conversation circa 1995 where Mike Karels (of BSD fame) talked about how you were lucky if hard drive caches didn't slow down the drive. The real performance of real file systems is a very complex problem. Subsequent to this we did some random benchmarking at the time and found about a 50/50 split where disabling the read cacheing would speed up rather than slow down real I/O performance. Part of the issue is that many drives embedded processors were not very fast so the hit of maintaining the cache was worse (since the disk to interface data path was usually a seperate fast path but cache would hit the embedded CPU).
In most OS/Filesystem combinations a file open/inital access is very expensive - lots of little I/Os to chase directories and file allocation chains until you finally get the data - then maybe a big read-ahead for you buffer cache that may or may not get used. Most filesystems are better at some things at the expense of others. So whether some amount of caching saves you any real elapsed time on an actual I/O operation is highly variable. There's also been discussion about how many filesystems (like UFS) were originally designed to try to factor in optimizations to deal with things like rotational latency and transfer speed based on rotation - that all goes out the window with any modern hard drive using zone recording/constant angular velocity (see http://www.isi.edu/netstation/zcav/zcav.html).
Right now transfer speed of the interface is a big limiting factor, as drive density goes up more and more drives can fill the pipe-at least on the outside tracks. So without new - and incompatible - interfaces you are likely to see less and less performance wins from a RAM based disk versus platter based.
IMHO - I think real wins in storage performance need to come from greater abstractions in the storage model. Imagine a device that you gave a complete path to and it then gave you a byte stream - let it manage the consistency, metadata etc. In some ways this is happening. Look at NAS versus SANs.
Network attached storage is better performance using interfaces with higher and higher bandwidths (GigE, USB 2, Firewire, Infiniband) so that it gets closer to performance with local storage.
Meanwhile local storage looks more and more like a network and has more and more features than simple block read/write (look at Storage Area Networks) - so the convergence is close in many ways.
I think real persistant storage will be using platters for a long time - until some new paradigm comes along. Look how long it's been since the venerable "Winchester" drives replaced drums, tapes, cards, etc. The RAM will be used where it's used today - as memory for CPUs to provide more intelligence and caching.
in step 4, you divide out (a-b) which you cannot do because it might be zero.
-tduffy
Use your solid state disk to store the journal files from your journeled filesystems. ReiserFS, XFS, JFS, any of those can benefit from this. Usually the journel file is in a fixed part of the disk, which means the disk heads must jump back and forth between the journal and the data. With an SSD for the journal, the heads can stay right on the data tracks.
Think of it as a ram-expansion slot. Imagine halflife without the "Hard disk access" pauses every 80 steps or so that cut noticably into the atmosphere but not really affecting the all-important god of "trigger finger" FPS. Imagine storing your windows swap file and your IE temp files on it, with the hard drive removed, and knowing that all that crap gets washed away when you power down your computer.
I went looking yesterday for PCMCIA RAM. I could find none!
My laptop is limited to 192 MB RAM, but otherwise very satisfactory. A PCMCIA RAM disk (say 512 MB or 1 GB) would greatly improve performance under loaded RAM conditions if used for the swap file, print spooler, etc.
Are any manufacturers listening?? There's a market out there for cheap solid state storage!
Why not put a few Mb inside the harddrive to store the FAT table... Cut down on the access time a little.
Go there, flash or html, solid state drives...been around for a while
According to AOL itself, Quantum Computer Services (which later changed names to America Online) released its first online service, Q-link, for some unnamed Commodore computer. The first product with the AOL name was for Apple ][ and Macintosh. I don't know if I, as a Mac user, should be happy or embarrassed by this. (:
There ain't no rules here; we're trying to accomplish something.
"Per unit of currency is a multi-national way of saying 'Per Dollar' or 'Per Pound' or 'Per Peso'.
It means how many bytes you can store for $1.
IT does not mean 'usable chunks'. It means exactl what it says. Per Unit of Currency.
Or, alternatively, you could back up one ram drive to another
What if you just used the RAM to mirror the contents of your Hard Drive?
Just load the whole damn partition into RAM at startup. or use some scheme to load part of it into RAM, then boot, then continue to load in the background.
Thrazzle@yahoo.com
But current PC's only support a maximum of a few Gigs of RAM.
With a seperate card... MORE. *grin*
thrazzle@yahoo.com
A few years ago, when memory prices dropped to about $60 for 32mb, I installed 64mb in my amiga, A system which isn`t especially memory hungry to start with. I created a RAD (ramdrive which survives a soft reboot) drive of 32mb, copied the OS to it, and booted from it. All my commonly accessed tools were there, aswell as the shared libraries.. boot time was almost nonexistant, application start was usually instant.. not so bad for a system that took 6 seconds to boot from HD anyway. Nowadays, it would be nice to do the same, enough ram to place your os and most commonly used apps/libs wouldn`t be too expensive, and would speed up the system aswell as save wear and power on the HD.
http://spamdecoy.net - free throwaway anonymous email - avoid spam!
If you guys can really get a gig for $US60 I envy you. Here, one gig is $300 ($US140) at the very cheapest. Here, a 20gb drive costs $250 (US$120) 20gb of ram (using cheaper 512mb sticks at current prices) = $6,400
;-)
We're not quite ready for solid state hdds, nobody would give up that profit margin.
Still, at a gig for $60, you guys must have some expensive harddrives for it to be cheaper than disk space
Send lawyers, guns, and money!
well then the answer is not a seperate gizmo. but support for more RAM in linux. that way standard users can use it. partition it and mount it as a disk partition and you got yourself a flying flash file storage.
aside, would you call flying+flash a superflash (ie. superman + flash)?
but then isn't 640k enough for everyone?
See http://www.storagesearch.com/ssd.html for a list of vendors. There are a number who make them in 3.5" configurations as well.
Most us SRAM which is far more expensive than DRAM, and some (like the ones with DRAM) have battery backup with a hard disk to write the data to in case of power loss.
SRAM is running over a dollar per Mbit last I looked, and I'm not sure how expensive MRAM is, but I'm sure it's even more so. Also, the density of the ram on teh chips is lower with the other technologies, making for a smaller number of SRAM chips. You can only fit so much in the 3.5 inch form factor!
Generally, these are not used for desktop systems, but for enterprise level systems where the access time is worth the extra cost, or military systems where reliability is essential.
Platypus Technology have already developed products that address many if not all of the issues raised. QikDATA Solid State Disk Along with providing vastly increased speed and efficiency, QikDATA maximizes data redundancy. The system combines a large and incredibly fast storage system with an internal UPS, and fully automated data back-up to multiple independent hard disk drives, should the host computer suffer a power loss. QikDATA at a glance. An ideal and secure way to maximize database application performance. Protected With internal UPS and automatic back-up to mirrored hard disk drives, QikDATA ensures maximum data protection. QikDATA can be configured without any single point of failure. Extreme Speed Takes advantage of the latest 64 bit, 66MHz PCI bus technology and SDRAM speeds - for sustained data throughput of up to 350MB/sec, allowing up to 40,000 I/O transactions per second. Scalable Each 1RU sized QikDATA provides between 1GB and 16GB of storage. Up to eight QikDATA units can be combined and spanned to create a single high performance drive of up to 128GB. Simple integration Has standard 1RU and PCI card installation. Can be formatted, partitioned or spanned like any other drive. Easily serviceable. Units are easily accessed for upgrades and part replacement.
MEMS does just this.
Its being researched more as a layer between ram and harddrive.
Noise Pollution
Here is a reality check on the practicality/feasibility of large capacity solid state storage...
***Performance: People here seem to be underestimating the performance of caching technologies. There are a number of cache levels on your PC (hard disk cache -> system ram -> L2 -> L1), and each one does a pretty decent job. Don't believe me? Create a large RAM disk and fill it with some typical applications, then start playing around. Your OS does a good job at keeping large areas of relevant data in system memory. You won't notice a huge boost in performance in everyday computing, except in limited circumstances. Granted, some of those "limited circumstances" are quite useful... You would, for example, be able to copy 1GB of multimedia files on the order of seconds instead of 1-2 minutes.
The key advantage of solid state storage is latency, not raw transfer rate... Latency plays a big role in overall system performance, and the near-instantaneous access time of an "SDRAM disk" could spell large performance gains in certain classes of applications, but it is NOT the end-all solution for increased PC performance.
***Power consumption & volatility: A number of people have posted that SDRAM is volatile. Well, duh, "just put a battery backup on it." Unfortunately, a number of issues come up when you try to do this. In the old days of DRAM, the DRAM controller or chipset would have to refresh the DRAM array on the order of 10-100 times per second. Remember, DRAM is capacitor-based storage, not transistor-based like SRAM or caches. Constantly refreshing these old chips requires constant power, and a lot of it.
Now the picture is somewhat brighter... Modern SDRAM chips have relatively low-power (8mW per chip), self-refresh modes which allow them to hold their contents without an external controller -- you literally just keep power supplied to the chip, and it will retain its contents.
Getting back to the point... Consider a 10 GB SDRAM disk. The largest volume-production SDRAM chips have 256mbit (32 megabyte) densities, and thus your 10GB drive requires 312 SDRAM chips. The number of chips itself may become a board integration problem. Also, good luck maintaining signal integrity at 100-133 MHz when your traces are 5 inches.
But for now assume these problems are solved... The real problem is power consumption in a "computer is off, my data is staying put" mode. Typical 256 mbit SDRAM chips consume about 2.5 milliamps during self-refresh, and so if your computer was off you would need 780 milliamps (2.5 *watts*) of continuous current simply to keep the memory contents intact! This would eat a $200, high-capacity 56 watt-hour LiIon laptop battery in a matter of 10-20 hours, so what would it do to some AA's from radio shack?
There *are* lower power SDRAM chips hitting the market (micron has some "battery friendly" SDRAM chips that draw much less than 2.5 mA in self-refresh mode, but they are FAR more expensive), but the issue remains.
So, in reality you need a hard disk that complements your SDRAM-based storage which keeps a copy of the data at all times.
***Reliability: Another issue is SDRAM soft errors... As SDRAM densities have skyrocketed and we move to 0.13 micron (and lower) fabrication processes, alpha particles hitting the die are becoming a problem. So, error correction is obviously a problem, and this would need to be solved (increasing costs and feasibility) in order for SDRAM-based storage to be as reliable as hard disks.
***Cost: Just because DRAM is unbelievably cheap now, don't assume it will stay that way. DRAM manufacturers are taking huge loses just to stay above water. My prediction -- once (if?) the economy recovers, you will NOT be seeing 1 GB of SDRAM for ~$60 anymore.
And even now, SDRAM-based disks could have their niche applications, but as long as hard disks stay so far ahead of RAM in terms of cost ($60 buys you ~40GB of disk, 1GB of RAM), I cannot see them becoming mainstream.
-Mel Tsai
The concept of a "ram-disk" or "solid state disk" dates back to at least the late 1970's. There was a company that would buy "reject" memory chips from the various manufacturers, and re-test them. A lot of them would have either the "bottom" half working, or the "top" half working. This company (sorry, I don't recall the name) would put these half-working chips into special boards that would only use the good half, and these, in turn, were shoved into "solid state disk drives" (the idea was to get as much speed as possible -- back when 6.0 MHz was a "fast" CPU). Remember, too, that disk drives were the size of a washing machine back then.
http://www.compaq.com/emea/inform/q299/html/storag e/storageworks.html
Solid State Storage is coming in about 4 years. It's called MRAM (magnetic RAM) and is a form of RAM that does not need constant charge to hold information. It has the added benefit that it is faster than current electric charge based RAM. Most people do not want to have to deal with power loss destroying data, so current RAM willl never make a popular storage medium. MRAM is the answer.
A wired article on it is here.
Motorola and IBM are both working very hard on this.
They've got two main product lines:
Their devices are supported on Sun/AIX/HP *and* Linux *and* FreeBSD, which makes it great for anyone who wants more speed from session caches and database logs.
I want any storage solution that is *QUIET*! so I don't have to hear the disk.
Read the answer above for the erase/write cycle problem.
Flash eprom has no seek time. This more than makes up for the slow write times. On a HD, the vast majority of time for most applications is spent during head seek, not actual write. Also, most apps do mainly reads, which are at RAM speed.
Thus, the only type of app which is affected is streaming recorders, such as a digital video recorder.
Exactly! Awesome idea... anyone know why it costs so much $? I've posted how to create this device yourself in a post below title "Summary Schematic". My design should only cost roughly $500 dollars to make.
Another issue that has been overlooked is the size of the resulting RAMdrive. You can buy 3.5" drives at 75 gigs. All of the current products that I have seen are at least full sized PCI cards, or a PCI card controller connected to a seperate RAMdrive frame.
The amazing thing about this is, the spinning storage is smaller that RAM drives. This is quite counter intuitive, but I believe that it demonstrates what engineering marvels a state of the art disk drive really is.
I do believe that RAM drive/ RAM storage technology can achieve mich higher packaging densities, but not using today's off the shelf memory chips.
-tpg.
While RAM is getting cheaper and cheaper, it also seems that Hard Drives are getting faster and faster. Now I'm not sure about all the technical details, or the exact rate at which the speed of Hard Drives is increasing, but it seems that we may someday no longer have a need for RAM. Is this right, or am I way out in left field?
hahahhahaha
that should really piss everyone off.
you are a Troll for laughing.
how dare you laugh, damn troll!
Hard disks, although a marvel of mechanical engineering, are still basically insane. Let's take the bits, put em on a plate and run them around in a circle. Then we will mave a sensor over the top and read/write away! This works and has worked for years. But the time is coming for technology to move on. The mechanical disk drive takes EONS of time to access data when compared to solid state electronics. We are running the rest of the computer at multi-GHz and still think that 10,000 RPM is fast storage. Someone posted that their RAID array can perform as well as an SSD. I have an answer for that, its called PHYSICS. Seek=zero. Rotational latency=zero. CRC=can't happen. Another thing: You never have to defrag an SSD, all files can be accessed with equal speed. SSD heads don't crash. Ever wonder why most high end storage arrays have hot-swappable drives? Scalability? No, it's because HDD's fail all the darn time and have to be replaced. I'm on a rant here, as you can tell. I better qualify myself: RAM has to get as cheap per bit as an HDD. We need MRAM or MRRAM so we don't have to worry about refresh. Also on the wish list: Put it on the Mother board. Why do you even need separate storage at all if your Mother board has a few TB of non-volatile super fast memory? One last thing. If you still think mechanical devices are king, then why are digital camera's and MP3 players so damn popular? Just my 2cp worth.
beacuse the RIAA won't allow it. And since the RIAA controls everyone and everything, forget it.
You can't recover data if it's all slag.
If you don't do that, RAM tends to keep values that are stored for long periods of times.
I wouldn't bet lots of lives on them not being able to recover stuff from RAM that's just been overwritten recently.
Cenatek makes a Rocket Drive PCI card that uses RAM for disk space. They say it "starts at $999" whatever that means. I went to their site and downloaded the RamDiskNT software. I use it for SETI at home and I ran some compiles on it at work. It kicks ass! I ran Intel's IOMETER on it and pulled 56,000 I/O's per second. That flat kicks the crap out of anything else out there (as far as I know). It also allows periodic backups and save and restore on startup/shutdown. Using SETI, I got a 30% improvement on processing work units. I used RamDiskNT at work for a while (It only costs $35 so what the heck). I saw a slight improvement on builds, but the process I use actually needs all the RAM I can spare and since the RamDisk steals my system memory, I don't win much. That's why I want their Rocket Drive product.--Its a RamDisk that uses RAM on a PCI card which will free up main memory for compiles. I am going to get one...I just have to figure out how to do an ROI on $999 for my expense report! URL: http://www.cenatek.com
It seems like the place where cheap RAM could be very useful would be in CD technology. Those discs take forever to spin up. If someone put a GB of RAM in a CDROM/CDR, they could read the disc into memory and serve files from there at a faster seek time...
Anyone wanna volunteer a drive? How about one of you hardware hack fellas? Tear apart your CDROM and buffer it!
Solid State drives would work best on a server platform... where there is constant, constant access to the files... as you eliminate the mechanical failure element of harddrives... (thrashing)... and the server is on 24/7 (anyway).
Take rpmfind.net, for example. Constantly the same files, are being downloaded over and over again... log files are being written out, files sent, etc. Once you take the harddrive out of the equation, the server can scale much higher to the amount of data it can spew out through a network card (assuming someday the networks will get with the program and we'll all have fiber to the doorstep instead of this bullshit we live with now (me @ 28.8 still through LURP, despite that I have 150+ boxes here).
The ideal server would be entirely solid state, have no powersupply fan, no cpu fan, on boot up load an image off of harddrive into the ramdrive, switch to it, shutdown the harddrive entirely... on shutdown the ramdrive would be copied back out to the harddrive (if necessary).
I once built 2 linux boxes to ship to Capt Crunch on the West Coast... I'm on the East Coast, and there never would be an opptunityy for me just to fly out there and kick the boxes when they puked. Crunchman at the time was a Mac guy. So I built them with P133s with no CPU fans (to die), and as much RAM as I could put in them as Cache to minimize thrashing as much as possible. Still Redhat every 5 seconds for some reason would write a log out to disk (Mandrake did this as well all the way up to and including 8.0) and I never could figure out what it was... but it drove me crazy... because I knew, writing to the drive every 5 seconds was a quick death sentence in the making.
root@rootpassword.com
in the early 90s, there were outfits that toggled up RAMdrives in the 20-meg and slightly higher neighborhood for about anything they could think of... DEC VAX-11/780 series, PC-ATs, on and on. cost umpty-thousand dollars, of course. now the hard disks that frame relay switches boot on are half-gig flash PC-card "disks", formatted FAT I assume, since you can manipulate them with W95. flash is not infinitely rewriteable, albeit supposedly well up from 10,000 cycles nowadays, so a cheapo RAID implementation with a standard HDA for powerfail and SDRAM sticks for power-on use would be the bargain-basement route now for REAL data storage service. that also is basically used in telco stuff all around the place, and has been for at least 3 years I know of. the only real magic point for PCs or servers is deciding when to take the backup "snapshots" due to the intensity of data changes and large delta-speed between the media.
if this is supposed to be a new economy, how come they still want my old fashioned money?
DVD technology solid state optical drive. In some way this was dvd material that could be read and written to without a mechanical component. Not heard a peep since but 2 gigs on a stick was promised.
I seem to remember back in my old Tandy CoCo days that there was such a device commercially available. I don't remember much about it but maybe someone still has some ancient copies of Rainbow magazine around. Gee how time flies - but remember the golden days of the early 80's when a 20 MB Seagate cost almost $300? sigh.
But....
They're expensive.
Keep in mind that the answer to the question "why don't they" is almost always to be found in the finances of the question at issue.
With that in mind, go visit here for exactly what you've all been looking for.
Btw/ if anyone wants to donate me a few (say 136) of the beasties and an controller to go with them, I'd be most appreciative...
We have been experimenting with a box provided by SolidData. ( http://www.soliddata.com ) The thing seems to work pretty well. Lots of redundancy built in. Kind of pricey, but the thing is blazingly fast.
That's a fairly narrow view. Yes, for read-only applications, flash is FINE. Hell.. Proms would be fine, and much cheaper. What do you think flash is? it's electronicly erasable read-only memory....
IF this is for a custom application.. fine. But if we're talking about a home PC.. they most certainly DO write to disk quite a bit. The discussion is about solid-state disks......
Flash is not a viable alternative for solid-state disks.
Disks write for both Swap, temporary files, etc. It hink you would be surprised how often your PC actually writes data to a disk.
Plus.. the number of erase/write cycles is also limited.. the flash wears out over time;.
I have to say, the moderation on Slashdot is just plain crap. Hundreds of boring comments saying nothing interesting on the subject, and two dimwits moderate this down. Fuck you lot then.
I agree. They should.
However, in practise, I have seen Windows NT 4.0 server operating as a file server to use only 1/4 of its memory for file caching. Temporarily it may exceed this, but it removes the exceeding part from the cache. Linux, working in a file server, allows caching of a much larger set of files.
I believe that Windows want to keep some part of the memory truely free due to some really strange technical aspects in the NT memory management performance. Perhaps they optimize the file cache size so, that they always get the minimal startup time for starting applications - and their file cache deallocation routines are just way too slow.
A NT workstation seems to use even a smaller portion of the memory for file caching. For slightly longer caches (after several minutes of doing nothing) only 10% of the memory is allowed for file caching. This can be mitigated by copying a few register keys from an NT server to a NT workstation.
However, due to the problems and inefficiencies in NT file caching it is best to buy hardware (a disc controller with lots and lots of memory) that does caching instead of the operating system. Then it almost really works. Another solution for the NT file caching problem is to use Linux ;-). Its file caching is quite efficient.
-- Imperial units must die --
It wouldnt be difficult to just backup only those parts of memory which have changed. Give each block in memory a change flag, when there isnt extensive use on the memory then the system takes its free time to backup changed portions and when the power goes out it can backup everything and shutdown.
Question
http://www.ironfroggy.com/
NiCad batteries are yesterday's technology. You really do want something like LiIon for this kind of duty. No memory, better charge/weight ratio, used in zillion cell phones, so it's cheap..
/. .. Maybe their facts are off by 20x, too?
With the sad fact of battery life expectance, especially if they're used, you'd *have* to swap the batteries every other year or so. And you still would end up with fairly short battery life due to the power-hungry Dram which requires refresh etc. Esp if you make this a, say, 4GB proxy for 1GB/s fiber..
If nothing else, this makes one wonder about the validity of those open source software gospel stories we usually get in
A 10G ram drive without battery backup would also make a killer Freenet datastore.
if my OS is smart enough, it will use as much as possible RAM for:
1) disk input caching - this means, thet file will be read slowly, from the disk, only first time. Next time it will be read from memory cache.
2) output buffering - files are actually written to buffer, very fast, and then, asynchronously, to the disk.
So, in theory, OS_with_good_memory_management+plenty_RAM gives you some great inprovement in I/O speed.
OK, a also want my machine to boot faster. Maybe, when flash memory will become cheaper than HD...
Regards,
Goggy.
The poster above you was actually wrong - The GeOS operating environment for DOS was originally written for the Commodore - I still have the 5 1/4" floppies for my C64.
When encryption is outlawed, ?o'AZ-,++o+i++##4AoA+-/-C++bI+/.+~
wich motherboards support most RAM?
Ram is not cheaper than harddisks per megabyte now, but it will be in the future. I've seen some charts which chart size of ram against time and do the same with harddrives. The breakpoint is somewhere between 2010 and 2015 where they will be equally expensive. That is of course if the trend of the past 20 years will continue the same way into the future.
How much power does it need then? Do you have any numbers?
The humour escapes me but somehow but you manage to be +3 funny in the end (+5 funny -1 underrated -1 offtopic).
please teach us all how to do this.
For large scale DDNS servers solid state disks are great for when you have to write huge zone transfer files very frequently!!!
You could just use a "ram drive" as a cache to reads off a hard drive and as a small buffer to write to the drive. With a good ups and shutdown software you could get the stuff written to disk before any major problems.
-- Tim
TKrabec Pahh
You can still get to the conclusion you're trying to reach by dividing by zero, but you shouldn't put such obvious mistakes in along the way. Try taking some remedial math classes, Mr. Coward.
Has anyone considered that if 2% of the PC using population wanted to set up a RAM array then the price would not stay as low as it currently stands?
I remember way back some of the guys I worked with at DEC Research had an Evil Plan(tm) to try to buy a bunch of RAM that had been culled at a fab plant. Apparently there were plenty of chips that "almost" worked but weren't fast enough (e.g. 100ns RAM that didn't work at 100ns but worked fine at 300ns...) or didn't store all the bits - the idea was to run them slower and keep parity for lossage. Interesting idea, anyhow, though I bet it'd be hard to get a microprocessor maker to sell their "seconds" - since they're "garbage" at that point, though, you could get 'em cheap, in theory. ;)
mjr.
In the mid 1990s I did commercial video game development. The largest hard drive I had during that time was 330MB, and it was never more than about half full. At home I had an 80MB hard drive for the longest time, but it was never more than a third full. Now I have a 6 gig drive at home, of which maybe 2 gigs are used. Most of that 2 gigs is for Windows plus some big applications, like Corel Draw and Delphi. That machine is used for commercial graphic arts plus software development in Lisp. I set aside a 2G partition for Linux for a while (Red Hat 5.2), but don't use it much.
My point? Solid state hard drives would work just fine, except that developers and consumers have gotten used to space being an infinite commodity. Games take 1 gig each to install. Windows XP takes over a gig just for the core OS. Now we have consumers buying 60 to 160 gigabyte hard drives. And the former is under $200. That much memory would cost thousands. But could I personally live within 1 gigabyte? Easily, provided I'm not using typical desktop OS that's designed to take up hard drive space (Windows, most Linux distributions, MacOS X).
If the $/GB of a standard HD is getting cheap, then check out what is going on in the FMD (Flourescent Multilayer Disk) arena. Take the exact size of a CD with sandwiched layers of clear plastic and flourescent dye (from 10 to 100 layers). It can be ROM, WORM, RAM or even a combination of each. The transfer speed is in the 1Gbps range but may go higher (the laser can read from all layers at once and keep it all straight). Check out http://www.fmdinsider.com or look up the company Constellation 3D (CDDD).
This blurs the line between solid state and MO because the disks are probably going to be priced at 1$/35GB. That makes it cheaper than a HD and faster too, and removable. Oh, and they can hold a movie in HDTV format (try that with DVD).
Also check out the FMC (FM-Card) which is a credit card sized media that holds about 10GB and would work well in MP3 players, cameras and PDAs.
=======================
Psyclo, the dark night.
Mike, the computer geek.
with AWE which is basically the old 16 bit
EMS redone in 32 bits.
It goes up to 30 gb.
I remember back in the day when my friend had a 33Mhz machine with windows 3.1 he had a 2M virtual drive to hold files so he could get some more speed out of them. I asked him what happened when he shutdown his computer and restarted it. He had a series of scripts that would run that would copy all of the files from the RAM drive to the hard drive in a temp folder so that he would never loose his data. On bootup and shutdown was the only times that it would write the data. The only flaw in this was that you had to shut down properly. I have been thinking that using this concept to run an operating system completly from RAM would be great but I havn't even begun to think what the scripts would look like. Any ideas out there? Doesn't matter what platform.
This basically boils down to a single rackmount
unit with slots for ram/sram chips and/or boards
along with some sort of raid front end hardware.
Could this be done over fiber optic networks with remote machines and current protocols (raw sockets)?
I remember someone's thesis from the early 1990s about storing read only files using the memory of diskless idle unix workstations...
I walked into a server with mirrored RAID 5 drive arrays. The performance was noticably slow. I don't recommend mirroring RAIDs (at least with both as hard drive arrays) from experience.
-m
http://www.invisik.com
The reason it is slow is because of the parity calculations of RAID 5. a mirrored array has fast read speeds [2N] and about the same write times [using cache improves this in write back mode]
From what I remember, RAID 5 is intended for reliability, not performance. Mirroring a RAID 5 should improve the performance of reads due to seek-time reduction, but it will make the already incredibly expensive writes (on RAID 5, at least) even more expensive.
In general, a mirroring RAID makes reads faster and writes slower. Why does a mirroring RAID make writes more expensive? Because all drives must seek to the location of the write in order to perform the write. Since the heads on all the mirrors may be scattered around the disk (a good thing for reads since it reduces average seek time on reads), the seek for any given write is as expensive as the most expensive seek across all the disks in the array. This makes the average for the whole array suck worse than it would for one disk.
As a separate issue, RAID 5 (which doesn't do mirroring in its basic form) still makes writes very expensive. Why are RAID 5 writes expensive? Because you have to update two blocks for every isolated 1 block update -- the block in question and its corresponding checksum block. Worst of all, if any one of the other blocks that share the checksum block aren't in cache, the checksum update is a read-modify-write cycle. OUCH! If you have lots of randomly scattered single-block updates, performance starts to suck pretty badly pretty quickly. On the plus side, if more than one block in a given update share a given checksum block, then the number of checksum updates go down since the updates can be combined. This means that the impact of RAID 5 is much less on large linear writes. In the best possible case, all blocks that share a given checksum block are being updated together in parallel with the checksum, so you can blast out the N blocks with N+1 parallel writes to the N+1 disks without any read-modify-write cycles.
(Note that it would seem that you can theoretically alleviate the r-m-w suckage I mention above by increasing your filesystem block size to at least N*physical_block_size, so that any update coming from the OS forces all physical blocks that share the same checksum block to be updated together. The suckage I mention above applies only if your filesystem's block size is smaller than N*physical_block_size. As I recall, physical_block_size is typically 512 bytes. For ext2, this means making your fs with a 4K block size instead of the default 1K block size if you're on a RAID 5 with more than 3 disks...)
--JoeProgram Intellivision!
I have exactly what you describe on my desk, they have been around for years. It is a ClipperII. It has a SCSI controller inside and 9Gb of PC 100 RAM for storage. A battery is built in which will keep it powered up for 4 hours. It was used for web content cacheing at my work, now it is used for my MP3's :-)
Funnily enough I have been thinking of upgrading the RAM with it being so cheap....
Carl
Incidentally, why is being able to "suspend to RAM" dependent on having lots of memory? Isn't what you're storing basically just the contents of your RAM, all of which is already there anyway? What constitutes the overhead?
One of the classic accelerators was the old Legato Prestoserve - it had a MB or so of battery-backed RAM, which was enough to provide a non-volatile buffer for the time it took for disk drives to write. Machines have gotten a lot faster since then, and disk drives now usually come with buffers of a few MB, but that kind of approach can still be a win.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
I primarily use RAMDISKS on Windows to accomplish the same thing - it's a convenient place to stash files I don't plan to keep, such as MSOffice attachments in incoming email messages, as well as to stash data I don't want on real disks, like decrypted emails (yes, I know they can get paged out, and there's memory persistence, but KGB/FBI/NSA attacks are really low on my threat models compared to generic theft.) It's an amazing performance win for many Windows applications, and Windows is happier running them from "disk" than running them from the temp files used by email while keeping the email messages open.
Both of those applications assume they're using main system RAM, and that they're relatively disposable - if the system crashes in the middle of a compile, you'll re-run the compile anyway. Some of the other approaches to RAM-disk boxes provide separate battery backup, which gives you persistence.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
It turns out that it's more difficult to get it right than one would first think. A number of the ideas posted to this discussion have already been incorporated in Andy's system; he has also addressed a number of other issues that haven't been discussed. See his HotOS paper for a bit more information.
Disclaimer: I'm deeply involved in the project. So naturally I think it's cool.
Yes. I think the real issue is this: You can only add so much ram to the common motherboard before running out of slots, even though you could easily afford to buy more ram. So.. the next obvious solution is some sort of expansion card that you can add more ram to. Of course, said card won't run at the same bus speeds, because it would be PCI or some such... so it doesn't make sense to use it as main memory. A good kludge would be to use it as a 'disk' and then use it for an ultra-fast swap (though not as fast as main memory, it would be way faster than disk access).
Also.. as to why you need swap. Perhaps you don't; swap is just there because you CAN.. ie: if we ever run out of memory, we can start using the disk... makes good sense.
Now who's going to design a pci board that has slots for pc100, pc133, whatever memory, with a memory controller/ide controller hybrid?
Just add room for some kind of cordless phone style battery and a small charger that can feed off of the pci power (or alternatively, a standard "drive" pwr plug)
Don't mess with drivers and shit like that, you're just limiting yourself to a specific os.
If you make it so it can plug into a standard IDE cable.. then you can use it with anything!
(a pci card wouldn't have much room for memory, but a 5 1/2 drive type thing would have more room..)
c'mon, someone build this...
It may be so $$$$$$ because of things like battery backup, low power RAM, and other crazy engineering marvels.
What I'd like to have is a PCI card with 4 or 8 DIMM slots on it, that can emulate IDE at any addr/IRQ (not just primary and secondary), comes unpopulated, and supports all DIMM sizes for which standards are in existance. I think such a card should be doable under $200 in quantity, although it's hard to say what quantities the market will demand.
now we need to go OSS in diesel cars
Oooops ! Sorry, that should read http://www.platypus.net/
:)
You'd think I'd know this by now !
The girl on the other address is quite cute anyway !!!
Cheers !
REO
NVRAM is the memory that needs to come down in prices for solid-state devices to become practical.
With normal memory, heat would be an issue if you put, say, 60gb worth of 512mb chips into a device.
You could, of course, use a derivative of RAID to provide a secure backup.
Any company that develops such a technology is going to have fluctuating memory prices to cope with during the development time, and likely investors are probably wary that during the time to market memory prices could easily go up again.
Or just as easily, DDR RAM might come crashing down during time to market, leaving the device at risk of being obselete as soon as it is released.
How is IBM doing with it's spin-based memory technology?
-- A change is as good as a reboot.
Any of you technojocks remember IBM's bubble memory attempts? Thought not...
1st. IBM is working on a new memory stick due to be released in 2003 that will be magnetic and not need any power to stay active. This means that when you powerup you will return instantly to the same status as when you powered down. Instantly is the Key word. Flash cards such as we use in cameras are a form of HD. I have a internal card reader in my PC with 2 180MB flash cards in that I can boot from. It is just something I have been playing with. Boots win98 in just under 4 secs. Down side is the cost of flash cars and their capacity plus the hoops you have to go through to make them bootable. Remmber the days of 8 bit, Atari for one. All you did was plug in a cart and turn on and bingo instant boot. An old technology with only one limitation and that bring cost and capacity. That will fall to the wayside soon as storage systems that spin and click are not long for this world. The hard drive has always been the slowest and weakest link in any computer system. Even the huge Tape spinners are slow and cumbersome and prone to a high rate of failure. Believe me solid state HDs are just around the corner.
If life is a bitch - Then what is death? I believe I will take the bitch.
Why use memory as a hard drive? What I'd like is a system that can save the state of the CPU and the CPU cache to a reserved memory location (what would you need? 4MB, max?), and then power down everything but the memory and an input device poller. Just like a laptop, but writing the system state to memory rather than a hard-drive. How much electricity does memory consume? How long would a UPS keep this going in save mode if power failed? If a desktop system had this and an LCD monitor, wouldn't this be as fast as a screensaver (aside from having to spin up the HD)? This would be enough for my needs; the boot-up lag is as much due to system initialization than hard drive lag on my system (and I don't reboot very often anyway), with a SCSI drive I almost never notice the lag to pull something off the hard drive, and with 512MB RAM I never notice the page swaps... but I would like instant-on/instant-off as a power saving feature.
Well, the current PC architecture supports only 4GB'o'RAM, 8GB with tricks, and exen 2gb may be a problem. So a PCI card idea is not going to work, you'll need to think up something non-standard (that's why current ss hdds are so expensive).
Your HD is on an interface with a theoretical max throughput of 100MB/sec, & your network card has a theoretical max throughput of 100Mb/sec. That is very very different from saying there is an 8x difference in performance between them. In fact the only time you are going to achieve a throughput on that hard drive of greater than the network card's 10MB/sec limit is during a large sequential read or write, and even then it is going to top out at maybe 30-50MB/sec.
More typical workstation use will be far slower, perhaps on the order of 2MB/sec, well within 100baseT capability. This is because your hard drive can only seek 100-200 times a second and there is only so much data that is needed from each access.
This is not to contradict your report that you saw bad performance when running something over some network. I'm sure you did. But it was not due to the throughput limit of the network card in your machine. A 100baseT card is plenty fast enough to support storage over the network.
I was a happy Quantum-Link user on my Commodore 64 with my 300 baud modem. IIRC it was around $15 a month for basic service and offered message boards, shareware and info services. You could pay extra for other things. It was frustrating though when you could read much faster than the text came through the modem. Although I don't think any compression was in use, so maybe 300 baud could have been usable with compression. I think 1200-2400 bps is the sweet spot for human computer interaction. 9600 and up is only useful for bulk data transfer, media, multiuser and the like. The fact that the web is unusable at 56k is disgusting to me; what wasteful protocols and designs people use now.
It's not clear to me why it's necessary to use batteries here. Why not just use a medium-to-large sized capacitor and an optional voltage regulator?
It seems unlikely the power requirements of RAM justify the cost and maintenance of a battery, and a capacitor would have the added benefit of smoothing out notches and spikes.