# So I wanna buy a Flash Hard Drive **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [July 6, 2007, 1:55am UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682 "2007-07-06T01:55:36Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![Surbey](https://avatars.discourse-cdn.com/v4/letter/s/4491bb/32.png) [@Surbey](https://boards.straightdope.com/u/Surbey)\ **Post date:** [July 6, 2007, 1:55am UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/1 "2007-07-06T01:55:36Z")
But I have no clue where to do it. Any ideas? I heard there were some large ones coming out soon. Any help? ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [July 6, 2007, 2:50am UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/2 "2007-07-06T02:50:23Z")
How much memory do you need? Flash drivers are pretty darn cheap these days, with drives up to 16G. I like buying these from [NewEgg](http://www.newegg.com/Store/SubCategory.aspx?SubCategory=522&name=USB-Flash-Drives) 1G drives are under $7, 2G as little as $13. Soon they’ll be putting them in cereal boxes. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [July 6, 2007, 9:07am UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/3 "2007-07-06T09:07:42Z")
I think the OP is talking about drives that are designed to replace the main hard drive in desktop and laptop computers - like [this one](http://news.zdnet.co.uk/hardware/0,1000000091,39258739,00.htm). My concern with these is the number of read-write cycles before failure - which I understood to be quite small compared to magnetic disk storage - have they solved that problem now? ---
**Author:** ![Szlater](https://avatars.discourse-cdn.com/v4/letter/s/90ced4/32.png) [@Szlater](https://boards.straightdope.com/u/Szlater)\ **Post date:** [July 6, 2007, 11:10am UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/4 "2007-07-06T11:10:20Z")
[QUOTE=Mangetout] I think the OP is talking about drives that are designed to replace the main hard drive in desktop and laptop computers - like [this one](http://news.zdnet.co.uk/hardware/0,1000000091,39258739,00.htm). My concern with these is the number of read-write cycles before failure - which I understood to be quite small compared to magnetic disk storage - have they solved that problem now? [/QUOTE] I don’t think that that’s an issue to be honest. The major issues are the staggering cost per GB (cost estimates are that in Q1-2009 1GB of Flash will costs 14 times that of the equivalent in magnetic storage), and disappointing speeds. In the benchmarks I’ve seen so far the solid state drives barely match the fastest magnetic drives. Both of these issues will improve, and SanDisk are claiming to have a 64GB drive that can load windows in 2/3rds the time a standard HDD can although this drive and it’s 32GB sister won’t actually go on sale until Q3-4 and prices haven’t been mentioned yet. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [July 6, 2007, 11:17am UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/5 "2007-07-06T11:17:54Z")
[QUOTE=Szlater] I don’t think that that’s an issue to be honest. [/QUOTE] Why not? ---
**Author:** ![Charlie\_Tan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/charlie_tan/32/12582_2.png) [@Charlie\_Tan](https://boards.straightdope.com/u/Charlie_Tan)\ **Post date:** [July 6, 2007, 11:28am UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/6 "2007-07-06T11:28:27Z")
If I were looking for high speed and realiability I’d buy this [Seagate SCSI](http://www.seagate.com/ww/v/index.jsp?vgnextoid=5f3d99f4fa74c010VgnVCM100000dd04090aRCRD&locale=en-US), 15k rpm, 3.5 ms read time. It’s expensive but worth it. ---
**Author:** ![St\_Ides](https://avatars.discourse-cdn.com/v4/letter/s/ccd318/32.png) [@St\_Ides](https://boards.straightdope.com/u/St_Ides)\ **Post date:** [July 6, 2007, 11:36am UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/7 "2007-07-06T11:36:35Z")
According to the various tech blogs I read, currently, for a 32gb drive, you’re looking at paying a premium of about $500-600 USD to get one on a laptop. Buying one separately? The only ones I can find are a max of 8gb and cost over $200usd, though on eBay, there seem to be some 16gb drives for well over $500usd, but I’m always weary of anything on eBay. And as far as performance goes, they’re supposed to blow normal HDs out of the water. From an article in January: > [@](#): > > The 1.8-inch SSD delivers a sustained read-rate of 62MBps and a random read rate of 7,000 inputs/outputs per second (IOPS) for a 512-byte transfer – more than 100 times faster than most hard disk drives. Fine, but the most notable detail in the press release is the price. According to SanDisk, their 32GB SSD could increase the end-user price by “around $600” when released in laptops computers in the first half of 2007. That’s down – way down – from the $900 to $1,400 premium we were paying for SSD equipped gear. But the prices are expected to drop by about 60% by the end of the year. I say wait until they’re more widely available and cheaper. ---
**Author:** ![Szlater](https://avatars.discourse-cdn.com/v4/letter/s/90ced4/32.png) [@Szlater](https://boards.straightdope.com/u/Szlater)\ **Post date:** [July 6, 2007, 11:59am UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/8 "2007-07-06T11:59:01Z")
[QUOTE=Mangetout] Why not? [/QUOTE] Wear levelling and bad block management. > [@BitMicro](#): > > Longevity/Lifespan > > Unlike DRAM, flash memory chips have a limited lifespan. Further, different flash chips have a different number of write cycles before errors start to occur. Flash chips with 300,000 write cycles are common, and currently the best flash chips are rated at 1,000,000 write cycles per block (with 8,000 blocks per chip). Now, just because a flash chip has a given write cycle rating, it doesn’t mean that the chip will self-destruct as soon as that threshold is reached. It means that a flash chip with a 1 million Erase/Write endurance threshold limit will have only 0.02 percent of the sample population turn into a bad block when the write threshold is reached for that block. The better flash solid state flash drive manufacturers have two ways to increase the longevity of the drives: First, a “balancing” algorithm is used. This monitors how many times each disk block has been written. This will greatly extend the life of the drive. The better manufacturers have “wear-leveling” algorithms that balance the data intelligently, avoiding both exacerbating the wearing of the blocks and “thrashing” of the disk: When a given block has been written above a certain percentage threshold, the solid state flash drive will (in the background, avoiding performance decreases) swap the data in that block with the data in a block that has exhibited a “read-only-like” characteristic. Second, should bad blocks occur, they are mapped out as they would be on a rotating disk. With usage patterns of writing gigabytes per day, each flash-based solid state flash drive should last hundreds of years, depending on capacity. If it has a DRAM cache, it’ll last even longer. [Cite](http://www.bitmicro.com/press_resources_flash_ssd.php) ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [July 6, 2007, 3:52pm UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/9 "2007-07-06T15:52:26Z")
[QUOTE=Szlater] The major issues are the staggering cost per GB (cost estimates are that in Q1-2009 1GB of Flash will costs 14 times that of the equivalent in magnetic storage), [/QUOTE] Some historical perspective… Just 10 years ago, the world was agog when IBM’s GMR technology brought the price of magnetic disk space down to 25¢ per megabyte. (And it was in a mind-blowingly large 16 GB drive. What could you ever \*do \* with all that space back then?) Now, we’re at about the same cost, but per gigabyte - the price of disk has gone down by a factor of 1000 (1024, actually) in ten years. Using \*\*Szlater’s \*\* figures above, that means flash disk will cost about two or three bucks a gig. Hardly a “staggering” cost. Right now, a 4GB SD card sells for about $40, or $10 per GB. Just for giggles, the first hard drive made back in 1956 weighed in at $10,000 per meg. At those prices, a 40 GB iPod would cost more dollars than my calculator can display - $41 million, just for the drive - and would be the size of a few thousand refrigerators - IBM’s 1956 RAMAC held 5 meg and was the size of two fridges. ---
**Author:** ![crazyjoe](https://avatars.discourse-cdn.com/v4/letter/c/f14d63/32.png) [@crazyjoe](https://boards.straightdope.com/u/crazyjoe)\ **Post date:** [July 6, 2007, 4:23pm UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/10 "2007-07-06T16:23:52Z")
So, Surbey, did you mean a Flash HD to replace a regular HD, or a USB Flash drive? Because (obviously) the advice is going to differ 🙂 ---
**Author:** ![Szlater](https://avatars.discourse-cdn.com/v4/letter/s/90ced4/32.png) [@Szlater](https://boards.straightdope.com/u/Szlater)\ **Post date:** [July 6, 2007, 6:40pm UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/11 "2007-07-06T18:40:36Z")
[QUOTE=gotpasswords] Hardly a “staggering” cost. Right now, a 4GB SD card sells for about $40, or $10 per GB. [/QUOTE] It’s staggering in comparison to the cost of your bog standard hard disk (for no real benefit, as yet), which is the point I was making. And I wasn’t talking about flash cards, but flash hard drives. When there’s a significant increase in speed over magnetic storage then I flash will take off. Trying to draw comparisons to the drop in price of HDD is a mistake as there was no real alternative to HDDs when they were coming onto the market. Flash faces considerable competition from existing technology which hasn’t reached it’s full potential (and probably won’t for some time). ---
**Author:** ![squeegee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/squeegee/32/14537_2.png) [@squeegee](https://boards.straightdope.com/u/squeegee)\ **Post date:** [July 7, 2007, 12:53am UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/12 "2007-07-07T00:53:14Z")
Is it possible that the OP meant he wanted to buy something like [this](http://en.wikipedia.org/wiki/Hybrid_drive) ? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [July 7, 2007, 3:48pm UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/13 "2007-07-07T15:48:27Z")
[QUOTE=Szlater] Wear levelling and bad block management. [/QUOTE] Thanks for that - looks like the coping mechanisms might be better than I thought they would be. I think there’s a gap in the marketplace for a device with flash storage and mirrored DRAM- on power-up, the contents of the flash memory are cached in DRAM, and that’s where all the work happens, on shutdown, they’re committed back to flash (I think this would be even faster than pure flash). Such a device could also contain a supercapacitor or small rechargeable battery so that it can still maintain the DRAM long enough to commit if the power fails. ---
**Author:** ![Mindfield](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mindfield/32/19759_2.png) [@Mindfield](https://boards.straightdope.com/u/Mindfield)\ **Post date:** [July 7, 2007, 4:26pm UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/14 "2007-07-07T16:26:11Z")
From what I’ve read, the MTBF (Mean Time Before Failure) of solid-state drives is [around 2,000,000 hours](http://www.overclockersclub.com/news/17707/). (Intel claims 5,000,000 hours for its SSD, as noted on the same link.) This exceeds standard HDDs which typically have an MTBF of anywhere between 300,000hrs and 1,200,000hrs. My main concern is read/write speed. Samsung’s own specs indicate a read speed of 64MB/s and a write speed of 45MB/sec. This sounds pretty good, but I haven’t been able to find any real-world speed comparisons between SSD and HDD. ---
**Author:** ![squeegee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/squeegee/32/14537_2.png) [@squeegee](https://boards.straightdope.com/u/squeegee)\ **Post date:** [July 7, 2007, 4:57pm UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/15 "2007-07-07T16:57:45Z")
[QUOTE=Mindfield] My main concern is read/write speed. Samsung’s own specs indicate a read speed of 64MB/s and a write speed of 45MB/sec. This sounds pretty good, but I haven’t been able to find any real-world speed comparisons between SSD and HDD. [/QUOTE] That’s not dissimilar to the [speed](http://www.reportlabs.com/testbed/version1/hdv1/hdt35in.php) of a fast 7200 or 10000rpm SATA drive. ---
**Author:** ![Mindfield](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mindfield/32/19759_2.png) [@Mindfield](https://boards.straightdope.com/u/Mindfield)\ **Post date:** [July 7, 2007, 5:25pm UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/16 "2007-07-07T17:25:33Z")
[QUOTE=squeegee] That’s not dissimilar to the [speed](http://www.reportlabs.com/testbed/version1/hdv1/hdt35in.php) of a fast 7200 or 10000rpm SATA drive. [/QUOTE] That’s not too bad, though still lacking compared to SATA300. I like the idea of SSDs, particularly for laptops. My storage needs are much higher than SSD can reasonably cover though, but if they can boost the speeds a bit more they’d make excellent OS/application drives. The largest I’ve seen so far is 128GB, which would be perfect for the power user to use as a bootup/app disk. The higher MTBF and added data safety features are well suited to that purpose. ---
**Author:** ![squeegee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/squeegee/32/14537_2.png) [@squeegee](https://boards.straightdope.com/u/squeegee)\ **Post date:** [July 8, 2007, 1:19am UTC](https://boards.straightdope.com/t/so-i-wanna-buy-a-flash-hard-drive/410682/17 "2007-07-08T01:19:36Z")
Well, considering the seek time for a flash drive is ZERO… it sounds like its pretty fast to me. 🙂