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Hard Drive of the Future: Ram Drive
benzick writes "3d Retreat has posted a hands on look at a 2gig ram drive called the Rocket Drive. Article blurb: Overall the rocket drive is the best in I/O performance I have seen. It outperforms U160 SCSI drives by almost a factor of two. Yet there are some drawbacks to the Rocket drive, foremost is the price, although listed at the end of the review is some alternative pricing options to make it less expensive. And the rocket drive can not act as a boot drive. Also, if you have some extra money to spend, you can use multiple rocket drives in parallel."
What's the point of this? You can already create RAM drives using the memory you have in your machine. You don't need a dedicated unit to do it. Heck, I could create meagre RAM drives on my 640KB Amstrad PC1640 (8086).
Why not just fit your PC out with 4GB of fast DDR RAM and do it that way? That memory would be far cheaper than this card.
mogorific carpentry experiments
It's another bullshit "hardware site" test.
The "benchmark" was a Photoshop filter on an image. It was twice as fast as with the SCSI disk.
This tells you very little about the relative performance of the drives since image processing is typically not disk bound.
And if someone trips over the cable, there goes your 2 gigs of data!
Thanks, but no thanks, I'll stick with mah good ole Winchester disks.
The hard drive is some ancient technology that is the *easily* #1 cause of all computer failures. Other than the cooling fans, they're the last moving parts, and the most critical ones too... A fan dying may cook your computer, but a hard drive kills your *data*. It's high time that something came along to replace those damn things. I'm typing this on my PC with a 2 drive RAID because I can't afford downtime or data loss. That really shouldn't be necessary any more. Bring on the alternatives!
1. A DRAM "drive" suffers the fundemental problem that if the "external" power source is lost, you lose everything on the drive.
2. 80-100 MB/sec sustained performance is nothing to write home about for DRAM performance. A RAID 0 stripe across 2 ATA drives could give you this same performance for about 1/4 the price without the power issue.
Although its a long way off, MRAM offers a much more promissing application in the area of high speed RAM drives.
Someone you trust is one of us.
Once you do this then ALL heads will be able to read or write simultaneously (in parallel) rather than one at a time as they do now.
Only question is -- how long till they decide to go for it.
I don't reboot my computer, might as well have a ram drive. Heck with something like tmpfs being able to swap out it would be MUCH better.
All we need is motherboards that accept more then a gig or two of memory.
ya but does it ahve an external power adapter you plug into the wall - or a battery on it?
Try moving to another machine with 2GB still alive on this thing...
Although a really good application for this would be that guy running the game cluster - or any game for that matter.
Run the whole game in the ram drive, everything, including the movies. Talk about speed.
It has been tried in the past, but the problem was that the heads would get slightly misaligned in time and you'd have to reformat too often.
To solve rotational misalignment in a platter-level RAID system, just treat the binary stream coming from each head assembly as a separately clocked serial stream, and combine them in the controller.
It's also straightforward to solve radial misalignment, that is, when one of the heads is slightly too far from the hub or too close to the hub. While the drive is idle, non-destructively reformat the disk continuously, reading an entire cylinder/sector pair head by head and then writing it all at once.
Will I retire or break 10K?
The article mentions that multiple RocketDrives could be used in parallel. That would seem only to be practical on 64-bit PCI buses. One RocketDrive transfers 80MB/s, which is close to the maximum sustained bandwidth for 32-bit 33MHz PCI. 132MB/s is the burst bandwidth, and cannot be sustained for very long.
In fact, I would think this drive would interfere with other devices that rely on the PCI bus. I doubt you could get 100Mbps (~12.5MB/s) on the same PCI bus.
"Sustained performance" is only a practical measure in a few uses (eg: multimedia). For most other things, latency (ie: seek times) has a far greater impact on performance. Even the fastest harddrives have seek times measured in milliseconds. With DRAM we're talking about nanoseconds.
The fundamental problem of "power is lost" can be solved easily by adding a battery on the drive.
Okay... I'll do the stupid things first, then you shy people follow.
[Zappa]
This is just sad...
3,000 dollars for something that has 2 gig of ram. I could get 2 gig of ram for a fraction of that amount... In fact, for the speed its giving, I could fill the thing up with sdram or edo ram...
This is something I could imagine being useful with my hard drive... Why don't they make a standard plugin for hard drives... Make it where you can add cache directly to the hard drive.
But wouldn't it be better to just have RAM instead of this?
Not if you're going to go over 4 gig. You'd then need a 64 bit solution for that... If, on the other hand, you could add MAJOR amounts of cache to your hard drive, it wouldn't matter if you only had 4 gig of actual memory. You could run IA-32 as long as you like. You could have potentially gigantic databases without worrying as much about disk thrashing...
It's going to be potentially a long time until a 64 bit winner in the PC world is declared... As time goes on, something like this may actually be viable. And as memory prices go down, we're going to be seeing a lot more 4 gig systems around...
Or am I on crack?
/^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$/i
As others have pointed out, this 32 bit PCI card pretty much sucks. It outperforms, what, a single U160 drive on a 32 bit controller? By only a factor of two?!?
You could easily smash the performance with a little U160 RAID on a 64 bit pci controller, and perhaps even with a single drive, though seek time would hurt a bit. At least it'd cost you a hell of a lot less.
It's not battery backed either, which is pretty useless for anything this might need to do. Heck, without battery backup, it proabbly can't even survive a reboot to get that precious data back after a system crash!
This reeks of an EE or Embedded Systems course assignment. It's barely a real product.
It makes more sense to max out your motherboard RAM and not have to go out to swap in the first place. If your motherboard is constrained the number in DIMM slots, you could always swap out the motherboard with one with more slots. Consider the cost of a motherboard ($300) vs. cost of a RAM drive ($3000).
Putting your swapfile on this doesn't make much sense. You'd be buying memory, putting it in a special card that makes the memory act like a hard drive, then making that hard drive act like memory. It would be cheaper to just buy more regular memory.
Tim
Omnia vestra castrorum habetur nobis.
Putting your swapfile on this doesn't make much sense. You'd be buying memory, putting it in a special card that makes the memory act like a hard drive, then making that hard drive act like memory. It would be cheaper to just buy more regular memory.
Except that you can have memory from here to the moon, yet Windows and various programs running on it will still insist on using disk-based virtual memory anyhow. With XP, setting the pagefile to 0 MB for all drives tends to work for awhile, and through several reboots, but then suddenly Windows will pick a drive and make a 1.5G (the same as the physical memory in my box) pagefile there, without telling me. It only does that if I had it at 0. If I have set some other value, like 512, that will stick. My system has over a gig physical free most of the time, yet still has about 150MB or so allocated as paged. This device turns that stupid problem into nothing, voila! I want it bootable before I will buy one, but I can't wait to have one and point all my apps' temp folders at it, like Cool Edit and such, that would be mega-sweet. Getting to set a nice big pagefile on it as well would be a nice bonus, as Windows could leave me the hell alone about such issues and I wouldn't care that it was being used needlessly.
This is potentially interesting, but there are several problems:
1. The pricing model sucks. The entry price of $399 is too high for a card with one chip and four DIMM sockets. And that only supports 512MB. To go to 1GB, 2GB or 4GB you have to pay hundreds of dollars more - even though the only change is a BIOS setting.
2. The RAM pricing is absurd. These guys need a reality check, pronto.
3. The board takes standard PC133 NON-PARITY RAM. No way in Hell would I trust my data to something like that. Honestly, this is just plain stupid. The board is too expensive for the home market and no-one sane is going to put non-ECC memory in a server.
[As a side point: Even using standard DIMMs, you could do some sort of block-ECC at the driver level (or in the controller chip) and use the fourth DIMM as a parity device to recover from on failures, like RAID-3. Alternately, you could treat each DIMM as a 48-bit device and use the remainder for ECC and Chipkill. There's nothing on Cenatek's site to suggest they do anything like this, though.]
There's a few other things that annoy me: the lack of specifications (while they have a list of approved memory modules, they point-blank refuse to provide the required memory specs on their support forum). Also, the board appears to require four identical DIMMs, which is a royal pain in the bum. Expandability? What's that? Low entry cost? Don't got one of those either.
So this board appears to be worthless for its target market and overpriced for anything else.
One-word review: Sucks.
Score: 3/10.
Memory is absurdly cheap, and a properly thought out board (even one that implements the ECC in software) at the right price has a market waiting. I know a lot of people doing embedded Telco apps would love something like this. This card isn't it.
The Platypus card is also over-priced, but it does support (indeed, requires) ECC, and also goes up to 8GB.
But if you are investing this much money into a RAM drive, you should just buy enough RAM so that you don't need a swap file at all.
It doesn't matter how much RAM you have. Fact: Windows uses RAM as cache and harddisk as memory. Windows will still swap like crazy after it uses up all the free RAM for disk cache. Don't believe me? Open a few web pages and keep their windows in the background for 30 minutes. This will guarantee that they will be first in line to be paged out with the following operation: Copy about 4 GB of files, like as would occur when you burn a DVD-R. Windows will immediately page out your background windows to make room for the file cache. Try bringing those background windows to the front now and watch the system hang for a few seconds while it pulls them out of the page file. And if you happen to be doing I/O and/or have a high CPU load going on at the same time as you try to bring those pages to the foreground, the wait may be quite a while... After the windows have been pulled out of the swap, switching between them is quick until you leave them in the background again and do more large file operations.
Very dumb but that's the way MS has designed this braindead VM system. And it has frustrated me to no end. On Windows 9x/ME, the problem could be easily fixed by adding MinFileCache/MaxFileCache settings to the system.ini file. NT-2000-XP, forget it. There is no fix that I know of. I've been searching for years for a solution to this. I've tried every cache adjustment program and the registry tweak to keep the kernal from paging (which doesn't work). My latest attempt to fix the problem involved using O&O's Clevercache, which had no effect. I now have some more memory on order to up my box from 640 MB to 1GB (the max I can stuff in, it's an old Abit BX6 Rev2). I plan to use about 666 MB for a RAM disk and put the swap file on it. Even though my application load is usually around 400 MB, which will cause immediate paging with only 333 MB available for the system RAM, I expect to see a huge performance boost over my current setup of 640 MB system RAM. Since Windows insists on running programs out of the swap file no matter how much RAM one has, this should finally fix the problem, albeit in a very kludgy way.
This usenet thread is somewhat dated though quite applicable: Why do I need a swap file with 128mb of ram
The reason why most people say adding more RAM fixes the problem is because most people aren't doing enough I/O to make the problem evident. Anyone who does AV editing and trys to surf at the same time (like me) will attest to the issue.
I don't get it.. let's assume, in the name of generosity, that U160 actually pushes 160mb constantly. Then the rocket drive pushes 320mb constantly. Now we've got PC3200 ddr ram that can theoretically push 3.2 gigs per second, while this rocket drive only does a tenth of that.
What's the damn point ? It has to go through some sort of slow-ass bus anyways.. it's not like it has precisely timed local access to the northbridge, like traditional ram.
It would be better for motherboard (and chipset) makers to accomodate buckets of ram sticks, so we can allocate a real RAM disk using 8 or 16 sticks of 512mb/1gb ddr.
-Billco, Fnarg.com