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The Joy of the Flash Drive
An anonymous reader writes "A post to the C|Net site covers the numerous benefits of flash drives, such as speed, temperature, and battery consumption. The perk author Michael Kanellos is most fond of? The distinct lack of noise. 'The notebook I'm testing--a Dell Latitude D830 with a 64GB flash hard drive from Samsung--hasn't emitted a sound in three days. Flash drives, which store data in NAND flash memory, don't require motors or spinning platters. Thus, there are no whirring mechanical noises. Compare that with my T42 ThinkPad. It sounds like a guinea pig got trapped inside, particularly during the start-up phase. Vzoooot. Cronk, cronk, cronk. Zip, zip. (Pause.) Gurlagurlagurla...zweeee. '"
It sounds like a guinea pig got trapped inside, particularly during the start-up phase. Vzoooot. Cronk, cronk, cronk. Zip, zip. (Pause.) Gurlagurlagurla...zweeee
I like the hard drive noises. Lets be honest here, they are soft clicks and chirps, not chainsaw noises. It gives me a non-visual feel of what the computer's up to.
-Grey
Silver Clipboard: Time Management Tips
I wonder what sound he makes...
"Vzoooot. Cronk, cronk, cronk. Zip, zip. (Pause.) Gurlagurlagurla...zweeee."
That's the pr0n your watching, not your hard drive dude.
Authority questions you. Return the favor.
Ought to be enough for anybody
I record my sleeptalking
Technically, they don't really become unreadable, there's just an uncorrectable bit flip or two (out of say, 128KB) and that block gets marked "bad" and then it's not used anymore. Whatever data it contained is still there though, and you could read it if you wanted to. That said, on an SSD there is an onboard controller that abstracts away the Flash itself, so I suppose that it might not provide any interface to reading "bad" blocks, other than that there's really nothing stopping you.
I remember when I had a Commodore 64, about 24 years ago, and solid state drives were 'just around the corner'. They have been lurking there for a VERY long time, but finally they arrived! I can't wait to get my hands on one. The next thing to emerge is Linux for the masses, which has been around the corner for about 12 years, if not longer. I'm very optimistic about that since the Eee PC turned out to be such a huge success last year. The future looks bright!
-- Cheers!
When you have that Intel chip that needs a fan that sounds like the Swamp Boat from the WaterBoy movie with Adam Sandler.
Every time I turn on my laptop and I hear the fan spin to life I think of that swamp boat and I can hear,
"My Mama says that alligators are ornery because they got all them teeth and no toothbrush."
"Wrong! Alligators are aggressive because of an enlarged medulla oblongata."
"No, Colonel Sanders, you're wrong. You're all wrong. Mama's right. Mama's right!"
"Somethin' wrong with his medulla oblongata."
I saw this link via The Inquirer - how to build your own from a bunch of RAIDed CF cards.
Assemble a SSD disk for less than 75 Euro
http://www.guru3d.com/article/memory/506
"Don't belong. Never join. Think for yourself. Peace." V.Stone, Microsoft Corporation
I've got a Sandisk Cruzer Titanium 4GB flashdrive. I've been using it since the day they were available in stores. As such, I've always kept it with me in my pocket. This wouldn't be a problem, except it's always exposed to heat and sweat. To make matters worse, I've thrown my pants in the washer and dryer *with* the drive about five times now.
It still works. I write and erase on the flashdrive almost daily. I easily copy 100MB files to it. No problems detected yet.
Dare I wash it for the sixth time?
Life is not for the lazy.
There are only two advantages spinning disks have over flash drives at the moment:
1) Density (disk about 4 times more capacity in same form factor)
2) Cost (disk more than 10 times cheaper for same capacity)
I expect flash to close the gap on density, but not necessarily on cost. However the cost of flash will ramp down low enough that if capacity is not your main objective then goodbye rotating media. In about 3 years more flash drives than disks will ship in laptops. For bulk storage, expect disk to stay cheaper per gig than flash for the next long time.
Have you got your LWN subscription yet?
...There is a pci card available that will take four CF cards and RAID-0 'em into a single drive. I was going to get it myself, but I slightly resented the poky pci bus at 133MB/s. In the future if they made one with 8 CF slots and put it onto a pci-e bus, I could then use 8 40MB/s CF cards in RAID-0 to make a single flash drive with 320MB/s on tap. That's a sweet-sweet prospect, but as yet they haven't made such a product.
I've been looking for Flash drives for a while now, and it seems the best option at the moment perfomance wise is the Mtron Pro series at 120Mb/sec. But 32 gigs will cost you 1129.
Which is why I wonder how Dell and Apple and everyone else can provide 64 gig SSD options for their notebooks for less than 1000 dollars. None of the brands had any info on the specs of the drives easily locatable, and I am worried these are the low end SSDs that are much much slower... which is a shame, because performance driven users would probably prefer better drives even for an extra 500 to 1000 dollars.
Later this year Intel is suppose to release 200Mb/sec 80G drives, which is really the only reason I haven't gotten one yet, but I have yet to find any info on pricing.
Flash media is considerably slower than hard drive media at the same price point. This is mainly due to economies of scale: there is a huge demand for low cost, moderately high performance desktop and laptop hard drives, while the demand for flash is for dirt cheap, low performance usb fobs. This is likely to change over time, but it will take years. Production methods for low unit-cost, high performance flash chips have to be developed, fab plants have to be built, all the usual problems.
Flash media (NAND-gate type) is fundamentally slower than hard drives for sustained serial write behaviour, where the seek penalty does not apply. This is not likely to change, since performance for both technologies should increase at roughly the same rate; so long as NAND-gate technology is the best we have, hard drives are still going to be around for those workloads that need that kind of thing (various forms of audio/video work, some database stuff, scientific applications). It's faster for the other major operating modes (all read modes, random-access-write, latency, etcetera), so is likely to give overall better performance for desktop computing workloads. There are experimental technologies in the labs that can outperform hard drives in the sustained serial write mode, but those aren't on the market yet, and may never be. They've been promising us MRAM for twenty years now, and still haven't come up with a product.
Limitations in current flash products mean that everything on the market is also slower than hard drives in the random-access-write mode. That's a problem with a known solution, there just isn't anything on the market that does it yet. This should change in the next generation or two.
Fifteen years ago, when I was a computer engineer, I could switch on a laptop with a dead screen and from the noises the hard drive made I could tell if the machine was otherwise healthy, what the OS was and whether or not it had an anti-virus installed. When you can't see the screen it becomes important to know at what point it's safe to power down the machine...
With a hard disk, a lot of bad sectors typically means that a bit of dust or similar has got inside, or the disk head is slightly damaged. Both of these will cause the rest of the drive to fail quite quickly, so once you get a few bad sectors it's worth replacing. With a flash drive, the cells are basically independent. With perfect wear levelling (which doesn't exist), then one cell failing means that the rest will all fail soon (assuming all were manufactured to exactly the same tolerances, which is also not true). In real-world usage, a flash drive will wear out quite gradually (over a period of a hundred years for half-decent modern flash). The only user-visible change will be that the capacity gradually diminishes.
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The problem is actually erase time - writing data to an erased block is fast (although not as fast as writing to a hard drive sector that is already under the write head), but erasing it ready for writing is extremely slow. The upcoming solution is to maintain a buffer of pre-erased blocks ahead of time; this is somewhat tricky to implement because it means data has to keep moving around the chip (a series of random writes to the same logical address has to be remapped so that it actually writes to a different physical block each time). There is no difficulty with erasing blocks in parallel, so it is merely a problem of managing all this, not a performance limitation of the underlying technology.
Also, the block sizes in the current generation of technology are too large. This is merely a production problem, which should go away in a generation or two.
Simply put: writing to a hard drive sector is faster than writing to a flash block, which is much faster than seeking to a hard drive sector, which is much faster than erasing a flash block. This part is unlikely to change. The other flaws in current flash products are likely to change.