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Seagate to Offer Solid State Drives in 2008
Lucas123 writes "Seagate will introduce drives based on flash memory in various storage capacities across its range of products including desktop and notebook PCs, according to Sumner Lemon at IDG News Service. The drives are expected to consume less power (longer battery life), offer faster data transfer rates and be more rugged than spinning disk, which has moving parts that can be damaged from an impact."
The rewrite issue has been rehashed a million times. It will be fine. I promise.
is projected out in the future? Normal hard drive capacity growth has certainly seemed to level off lately and perhaps is stagnating (so it seems to me). Yes, flash has grown astronomically the past few years, but is it sustainable to the point of meeting and exceeding conventional drives?
If we had the rate of growth in conventional drives that we had a few years back, we would almost certainly be looking at multi-TB drives right now.
The headache now is that most file systems are optimised for mechanical based storage media so wont this also mean we will have to look at changing to new file systems ?
There are different grades of flash chip, with varying amounts of write cycles. The problem with the kind of flash that you get in a usb keyring is not that flash is limited in the number of writes, but that cheap low-end flash is. The kind of solid state storage in a drive can take millions of write cycles, which combined with a file-system that spreads the writes evenly across he chip will give a decent lifespan.
Cost is still a major issue though. The article only has one number in it, that densities will go up to 160Gb. Do you think they'll take a cheque for that, or you do you have to spread and touch your toes in person?
Slashdot: where don knuth is an idiot because he cant grasp the awesome power of php
I think the 160 GB refers to the hybrid disks Seagate also has in their lineup (which are also mentioned in TFA). Would be more logical too because even with todays cheap flash prices, a 160 GB flash drive would still be relatively pricey.
Do the math. When rewrites were a problem, how big were the chips? How big are the chips now? How many more writes are possible now? The amount of data that becomes a problem is astronomical at this point...the 'rewrite problem' will kick in long after a spinning disk has found a reason to die.
Nerd rage is the funniest rage.
Nobody mentioned the noise! SSD's are silent.
I can't wait for ssd's. Every hard drive I've owned has been noisy and they drive me nuts.
As for durability... hrmm... maybe in its current state, flash doesn't last that long. But, the potential has got to be better than a constantly-spinning platter of disks. I've never had a RAM stick, or flash card die on me, but I've lost many hard drives.
Also, I think there may be greater potential for memory density. Spinning platters inevitably have wasted space, forming a cylinder in a rectangular prism.
I'd be interested to see the effect of SSD's on prices of normal hard drives. Normal HDD prices have been plummetting rapidly over the last couple of years - I wonder if the lure of flash will push them down further.
I think with capacity being so important, price/MB will be a big determining factor in getting flash into enterprise storage. I think the desktop, and (obviously) laptop markets will lap it up first.
Am I safe in assuming SATA transfer rates are sufficient to handle a SSD?
Will it move choke points elsewhere on the system?
I'd like to know what other practical benefits such would have other than lower power consumption and durability.
Someone hates these cans.
It's not all that bad. If I remember correctly, most flash memory can take 100,000-300,000.. according to wikipedia:
"while high endurance Flash storage is often marketed with endurance of 1-5 million write cycles"
I did a small research project (informational) on flash stuff recently for school, I believe solid state hard drives back in June or so were said to have about 2 million writes.
2 million writes per sector. You can always move the information around, and algorithms are being written to do that.
But, with all that, seems like hybrid drives would be the way to go right now.. after all, there's no limit on READING from solid state drives, just writing.
Not trolling, I just havent ever seen hard stats on current flash/solid state durability over time recently.
Take a 40GB hard drive, and pretend it's Flash memory. If you wrote 40GB worth of data to it every single day (with the circuitry inside a drive to spread writes out over cells evenly), then you would average 1 write per day across each cell. Flash memory can be written to a minimum of 10,000 times before dying, most is even more reliably by an order of magnitude (100,000 writes). Assuming we have crappy 10,000 write limits, we could write 40GB to the drive every day for 10,000 days, or 27 years, before failing is an issue.
Looking at the 40GB drive in one of my machines, the total writes in its uptime comes to about 800MB, which is a shade under 24 hours uptime. That's 800MB worth of writes in a day, 50 times *less* than writing 40GB to the drive every day, so a 40GB flash drive at my current usage rate could be expected to last 27 * 50, or 1350 years.
A lot longer than I have to worry about. The numbers are going to differ for some people, but the initial stats work out - few people would write to every cell every day, and even then that's decades worth of use.
I have been researching some of the more current SSD drives lately, and I know that they greatly improved the technology/algorithms behind how they write data to the physical memory. Most companies use some kind of wear-leveling techniques that evenly distribute the writes over the entire surface of the disk, maximizing the disk's life span. I have also read that the different-sized memory modules have different physical characteristics such that smaller modules are actually outlived by larger ones.
I can't give exact figures, but I've seen comparisons showing a reasonable life span (>20 years @ 100GB of writes/day) - some of the numbers are even comparable to those of spinning/mechanical hard drives. Considering how often mechanical hard drives seem to fail, it doesn't seem that there will be any major roadblocks in terms of reliability.
I know what I've written is mostly qualitative (apologies on that), but I know the research into how to mitigate the problem of life span has truly advanced in the last few years as interest in SSD has increased. Jim Gray of Microsoft Research fame, predicted that SSD would replace mechanical drives not far off from now. Check out his paper "Flash Disk Opportunity for Server-Applications" for more on that.
SixD
I think that may have been a problem on older flash drives, especially b/c fat32 keeps the fat all in the same place. But newer models have built-in wear leveling. The only thing you'd need to do would be to turn off seek-time optimization, as there's no rotating disk.
A more interesting question would be how these things hold up when used for swap.
All modern flash drives use write levelling to ensure writes
are evenly spread across the device.
This article
takes those numbers and using a hypothetical "write logger" app that
continually writes, estimates an average life of 51 years.
MTron specs for their SSDs estimate:
So lets lay this one to rest. SSDs are worth it.
I wonder to what extent current high capacity HDs owe their high power consumption to the needs of high performance (low access time and high bandwidth). But if a large flash cache (say 4-16 GB) buffers the HD, then the HD mechanism could be redesigned to a much lower spec. I'd bet that a ultraslow 300 RPM platter with a stepper-motor head (versus the 4200 to 7500 rpm platter + voice coil technology currently used) would provide adequate performance (and low power consumption) if flash handled the vast majority of accesses and high speed read-writes. The physical disk mechanism would only need to support a bandwidth of about 2-3 Mbytes/sec (for a sustained read of an HD video stream) and flash would provide the 80-150 MBytes/sec burst bandwidth to compete with current laptop drives. (Hardcore video editors wouldn't use this device, but then they wouldn't use most of the low-power laptops on the market anyway).
Two wrongs don't make a right, but three lefts do.
ZFS will. Traditional RAID may suffer though: all the drives will have the same write pattern. Make sure your flash drives aren't all the same age!
Do you even lift?
These aren't the 'roids you're looking for.
How do you know that the drive will evenly distribute writes per cell? Its more likely that some cells may remain untouched, which other cells may get written or changed much more frequently.
In America we are imprisoned by our fear of them.
You just need to have some spare space (say 20% of additional capacity) and dynamically remap areas from the 'working' part of the disk.
I did some poking around the net for information on NAND write cycles. They've already been quoted in the comments here (100,000 to 2,000,000) so I'm just going to post this neat white paper I found on Zeus drives that explains the endurance they get from their SSD Drive. http://www.baydel.com/images/gallery/NAND%20flash% 20resilience.pdf
New! Device Legs: These legs will help your poor OEM installed product escape any hamfistedness it may encounter. Ava
The drive controller will do wear leveling, so it will not rewrite the same bits over and over again, even if the OS thinks it does. This has also been rehashed a million times.
Relax, they still sell mechanical hard drives.
How big would one of these things be if they were made using vacuum tubes?
What?
Next thing you'll be saying they still sell RAM sufficient for your working set.
The integrated electronics do it for you, otherwise the flash drive would 'fail' sequentially, in order of cell use, and you'd steadily see your reported usable capacity dropping. Does not happen. In my experience, flash drives just keep on working - even in intensive use - but then just somtimes fail suddenly and totally, with no warning.
Somewhere on the order of 1 million erase-write cycles per bit. That should be more than enough even for swapping purposes.
*sigh* back to work...
That's why you don't *do* that. Or, more precisely, why the SSD shouldn't *let* you do that. All it needs to do is keep some hidden spare space (10%? 5%? 1%? I don't know, but it's not huge) and dynamically remap sectors to balance writes. If you have GB of remapping room, even a "full" disk with heavy load would take a long time to wear out.
CompactFlash to IDE adapters can be had for $5 or so and work fine with most motherboards.
Given your comment... what does this do to data recovery, when one DOES fail?
~REZ~ #43301. Who'd fake being me anyway?
...and at that rate you lose 1 sector. That's assuming the disk manager was written poorly enough to actually do such a strange and unprecedented thing.
New! Device Legs: These legs will help your poor OEM installed product escape any hamfistedness it may encounter. Ava
For that matter, how come we never saw magnetic drives with builtin RAM caches in the GB scale, occasionally written (in parallel) back to the magnetic disc for reliability?
Possibly because you weren't looking. For all I know, they still exist, but the vendor we got one from went out of business a few years ago. They sold full-length PCI cards packed with 8GB of SDRAM -- and they had larger models -- that presented a SCSI interface to the system and, with the appropriate driver, could mirror to a magnetic drive. The cost was stratospheric, and our storage needs soon outgrew the available space. We also found that not as much of our processing was I/O-bound as we thought. Other than that, it worked great. Given enough money and a motherboard with a sufficiently large number of PCI slots, it might be the ideal solution for certain niche applications, but the cost and size constraints otherwise make them a poor substitute for magnetic drives in most cases.
That said, it was pretty cool to be able to reformat the "drive" in a few seconds.
Proud member of the Weirdo-American community.
If we go back about 20 years, hard drives were for non-volatile fast-access storage, and tape drives were for backup, bulk data storage, archiving and sometimes data transfer (when there was too much for floppies.)
Now that flash is reaching the point where we can contemplate using it for the primary non-volatile storage niche, we may see hard drives being displaced into the backup/bulk storage/archiving niches. If so, expect to see increasing emphasis on ways to hot-plug hard drives into your computer, and increasing emphasis on price/GB and decreasing emphasis on performance and possibly per-drive capacity.
We'll really know we've reached this point when hard drives are used as a medium for delivering software.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
Will partitioning the media be physical? For example if I have a 20Gb drive, unpartitioned it will last (2x10^6)(10^6) erase-writes balanced across the whole disk. By partitioning won't you physically circumvent the whole wear leveling idea? Maybe not completely circumvent but you would kill erase-write potiential by a factor of 20 in this case, and since a swap partition can get pretty intense you might run out faster then you think.
A loop, by its nature, continues. If that didn't make sense, start reading this sentence again.
Flash drives are basically goodness by most measures -- more reliable, quiet, less power use, and faster (or at least, the potential to be far faster than mechanical drives).
... POP!". The motherboard was fried, and as it turned out so was the hard drive, probably due to a voltage spike. But a data recovery service was still able to recover the data from the physical platters. I guess with flash drives, those days will be history -- when a flash drive is gone, it's probably gone for good.
But a friend's recent experience with liquid spilled on a laptop illustrates an interesting point about recoverability. The laptop went, and I quote, "bzzzt
Guys, hate to break it to you, but anyone who wants to be running on solid state, is.
3 IDE-CF adapters cost me 8$ including shipment on ebay last week. My game box runs of a 16GB CF card (200$ - new - on ebay, available for months now) with vista (yes, vista on a 22MB/sec CF, though I've gotten it there via ghosting rather than via a regular install), and my living room PC runs XP off a 2GB CF card that cost about 25$ new (again, ebay price, store prices typically a tad higher).
Yes, 20MB/sec is less than the 50-70MB/sec read speed an average harddrive gives, but that is offset by near-zero seek times.
If under windows, make sure you turn off:
* SWAP
* ntfs Access time writes (fs tuning utility, one command from shell, or a reg key)
And if you want to be even more thorough and flash-friendly:
* 8_3 filename writes (in ntfs every file has two filenames one that is backwards-compatible to 8_3 naming. No need to waste CF writes on that)
* Any software that routinely writes stuff to disk.
If you're fanatic, do:
* Event logger
* Indexing
If you want >16GB, you can buy several, then use LVM/dynamic disk/multiple partitions depending on your OS to use that.
I just have the core 16GB (about 8GB occupied) on the game box, and do the rest of the storage (aka keep the Program Files directory) on the RAID5 fileserver over Gigabit LAN, which gives me about 40MB/sec read and write, which is IMHO sufficient. Were I not to rely on that, I'd get another two 16GB cards on a CF-IDE adapter, plonk a RAID0 on them and voilla (assuming you can get windows to make dynamic disks of removable storage, which the CF cards are still recognized as, even when on the IDE bus), which I am by no means certain.
If you're on Linux, no problem there. anything and verything can be raided and LVM'd at will.
A RAID0 of these would cost 400$, give 32GB and give about 40MB/sec performance.
So no need to get overly excited with SSD. They're just an overpriced nicely bundled version of what is already cheaply available, kinda like external harddrives. And they'll keep on being that for a while yet.
-
Every time a story comes up on /. about SSD, this is invariably the first question in the comments. Seriously, I've seen like seven of these now. Yes, the writes are limited... but with efficient algorithms to spread the writes correctly, and operating systems that are aware of the media, we are talking 10-20 years before it becomes an issue.
No company would want the nightmare of releasing a product that is going to fall apart in 2 years. It would tarnish their reputation forever. Think of the notorious IBM Deathstars (now Hitachi). Those were even on warranty and many will never buy them again because of the hassle of returning so many.
Self-referential Sigs are cool on /. these days...
54
How do you know that the drive will evenly distribute writes per cell?
You don't. But what we do know is that if you take a balanced 6-sided die and roll it a large number of times, the distribution of faces to come up will be uniform. That is, each face has an equal chance of being selected. So if we randomly choose a sector and write to it, the wear over large numbers of writes will be uniform over all sectors.
Its more likely that some cells may remain untouched, which other cells may get written or changed much more frequently.
That's why if you happen to hit a cell that already has data, you relocate the existing data and write to it anyway. Even though you are using more write cycles, as long as you don't max the capacity the disk will wear out evenly and you won't use up all of the write cycles anytime soon. Assuming a 40GB disk with a poor 10,000 write cycle limit, that would be 400,000GB of data to write before the disk completely fails. That means over one year (365 days) you'd have to write 1095GB of data a day to kill a disk that had the most optimal wear-leveling algorithm. If the algorithm required an average of 2 writes per every 1 write of actual data due to moving around data, then you'd still have to write more than 500GB to kill the disk in a year. The truth is most people don't immediately max the disk until a good year later if at all. Even then, they would only write in the 10s of GBs unless they totally stripped out their ram capacity.
So it's safe to say that the write cycles are nearly unlimited for useful purposes as long as we attempt to do some kind of uniform distribution across all the cells. Most tech only has a max life span of around 10 years so the write cycles for even poor flash cells is pretty much unlimited for it's useful lifespan. In a laptop or portable device, I'm willing to bet your battery will give you problems before any other hardware. Battery recharge cycles are usually around 500 cycles, yet nobody complains about batteries like they do about flash write cycles.
Flash drives simply don't write the same first bits over and over again. Their firmware is programmed to 'intelligently' spread written data across the entire storage area as fairly as possible.
Between this, massive storage capacity (think: 'dilution') and what will surely be engineering improvements, flash drives should prove to be very reliable.
I for one, welcome out solid state overlords.
Fact: Everything I say is fiction.
There are many techniques. If you really want details, get a book or hit wikipedia. But to give you a general idea:
Each block has, infact, a bit more storage than the amount exposed. There are error-correcting checksums and stuff, allowing the drive to detect (and sometimes correct) errors, among these are, typically, a counter saying how many times the block has been written to.
If the drive notices that one block has a lot more writes than the average block, it can swap the contents of those two blocks internally, and then make a note of this swap. (just a simple mapping 0x000FE37 isat: 0x00A32B) The host-OS never even notices this, it keeps asking for block 0x000FE37, and keeps getting the same content that was always there, only that content is now *physically* stored somewhere else.
It's a lot as if your office is worn-down and needs to be redone, and management puts you in a different office, but let you keep your old phone-number. People calling for you won't even notice that *physically* you're now somewhere else, all they know is, they dial that number, they reach you.
Every OS with virtual memory does the same thing to RAM (though for a different reason) the logical adresses that the programs see are related to the *physical* (actual) ram-locations by a lookup-table.
It's *really* not a hard problem to solve, and it's been thoroughly solved for literally decades. Thus you really *CAN* assume that the entire drive is (aproximately) evenly used. Which means those calculations aren't bullshit afterall. Even if you just constantly rewrote a single block, what would happen is after a while (say 1000 writes) that block would, internally in the flash, be replaced with another physical block, if you write another 1000 times that'd happen again and so on.
Yes, there's a sligth overhead: Every time you do 1000 writes, the flash needs to do (aproximately) 1003 writes and 3 reads. That is a small overhead though, and it can be reduced by upping the constant from 1000 to 10000 say. (which would result in wear being sligthly less evenly distributed, but nevermind)
You are only the five billionth reader that points out that "flash drives have limited writes". This is true, but, as five billion other readers have responded already, this is not an issue. The SSD drives that are being sold have have an integrated controller that spreads out the writes evenly over the disk. That way, the expected lifespan of a SSD drive is 10-20 years at least, which is about the same as regular hard drives.
So please stop spreading the myth that SSD drives should somehow be inferior to regular hard drives in this area. The REAL disadvantages of SSD drives is that the sequential read time is lower, maybe a tenth of a regular hard drive. On the other hand, it is possible to improve this, so it will of course not always be so. In all other areas, power consumption, seek time, random reads, heat, and noise, the SSD drives completely outclasses regular hard drives. The only disadvantage that will last is that of cost, but given the superiority of the technology, demand will be crazy, and prices will go down a lot.
This will be pretty similar to how flat screens took over the market from CRT monitors.
Form factor and driver loading is the problem.
You can easilly buy wiring/form factor adaptors that take a CF card and fit into a laptop drive bay (though admittedly laptops moving to sata will make this harder). You can then install any OS you like (space permitting but you can easilly buy 16 gigabyte CF cards which should be enough for XP and I suspect if you look arround you can buy ones big enough for vista) with no driver issues at all since as far as the motherboard is concerned it is a standard IDE drive.
note: i'm known as plugwash most places but i screwd up registering that here somehow in the past and now can't register
>>How long of a warranty will these have? Doesn't flash memory break down after a good number of rewrites?
e _frm/thread/136aad9133d01bb7/9c5bce4697be4e1f?lnk= st&q=&rnum=8#9c5bce4697be4e1f
But it's better than having to park my hard drive heads every time before I shut down. Sometimes I forget, and then that data is corrupt. Maybe one day Hard Drives will park themselves at shutdown.
Reference;
http://groups.google.com/group/net.micro.pc/brows
(Tone:Sarcastic/Funny)
Good reply from AC, just to add to that.
1. In my experience, flash memory can sometimes fail totally. This may be due to it being often removable, and accessed in rather non-robust ways, (USB ports, card readers). Hence (presumably) gets nuked by static etc. My attempts at recovering such 'dead' flash devices have not been great, so far. When it's dead, it's dead...even re-format does not work sometimes.
Presumably, internal flash 'disk drive replacements' would be rather more robust.
2. When flash drives first came out, 'classical' data-recovery tools seem to have difficulty recovering from acidental deletes and formats etc., since they seemed (I'm not an expert) to be looking for HDD-like behaviour. I remember reading an interesting paper long ago about the consequences of 'random walk' data storage for recovery... Since then, things have improved, and a lot of tools claim to be/are able to recover data from flash. Of course, I never need these, since I have good backups, ahem.
BTW, I was recently at a client site (for once without my PC and DVDs, CDs, flash drives etc. stuffed with tools) when the sales manager wiped his hard disk. Their in-house IT support was - as usual - no help. I download one of my fav. simple tools,
http://www.snapfiles.com/get/restoration.html
ran it from a USB, copied the undeleted files to a USB HDD and bingo! Another happy customer.
Check it out - if the PC boots (into windoz) it does the job...
That's not what I meant. The form factor problem is the one of being able to fit enough chips, passives and PCB into a 1.8" or 2.5" enclosure and still be able to have a decent amount of storage (and not burn up).
In your example, yes, CF will get the job done for now, but flash transfer rates are increasing rapidly, latencies are decreasing rapidly and we should be seeing SSDs by the end of next year that contain purpose-built components designed for high speed, low parasitic loading and low latencies. Even now a 32GB or 64GB SATA SSD is a much more elegant solution than a bunch of CF cards plugged into adapters. And in the case of a notebook, a 64GB drive can easily be the only mass storage device you need.