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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.
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 ?
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
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.
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.