When can I expect a Flash drive computer?

April 13, 2006 5:31 PM

With the rise of flash drive technology, it makes me wonder why flash drives can't be used as primary hard drives in computers/mp3 players/ handheld gaming devices, etc. Could an OS conceivably be put on a flash drive? One that boots up almost immediately? For all our advancements with computers, it seems like boot times are getting longer, if anything. Flash drives keep getting bigger and bigger, up to 10 or more gigs nowadays, so when can I expect the computer manufacturers to roll out Flash drive computers? 5 years? 10? What are the technical limitations/challenges of Flash drives?
posted by zardoz to computers & internet (27 comments total)

Good question. Imagine generic workstations everywhere, and everyone just carries around the same flash drive and plugs it in wherever they go. The ultimate in mobile computing. Expect it to happen.
posted by Ironmouth at 5:36 PM on April 13, 2006

It's up to 64 GB now

I'm sure once the price goes down a bit (ie probably around 18 -36 months if we apply Moore's law). This will start being more common. Especially in laptops.
posted by bitdamaged at 5:46 PM on April 13, 2006

two main ones. one is that flash is fricking expensive. see, for example, this 12GB Pretec CF card. Froogle turned up some 8GB ones for a good bit less (still roughly $250-450 range still though).

second is that flash wears out. you can only write and erase from the device so many times before you start getting errors. most modern OSes have virtual memory, and having virtual memory on a flash disk is a good way to kill the disk pretty quickly. (this has gotten better recently.)

(there's a third, smaller one - flash isn't really fast either. hard drives still outstrip flash. drives based around regular volatile memory, like DDR SDRAM, are very much faster than hard drives but are also a lot more expensive.)

that said, there's no real reason why you can't do a flash memory hard drive. in fact, people who build very small computers use it. Compact Flash is very much like IDE - if you want you can have your home PC boot up off of a flash disk. you're going to spend a pretty penny to get a card sizeable enough to do it, though. also, many smaller devices, including your router, cable box, and a good deal of MP3 players, are already using flash for their OS.

(FWIW, IMHO boot times are getting shorter - OS X seems to boot faster with each major revision, and XP boots up a lot faster than 2K did. but I very rarely turn off my OS X machine - sleep works very well. and you can Hibernate on most Windows machines. both methods - sleeping and hibernation - have the added benefit of keeping state. if you're looking for a way to speed up your boot time I'd try that instead of doing flash or DRAM-based disks.)
posted by mrg at 5:48 PM on April 13, 2006

I don't want to sound snippy, but did you do a google search before asking this question? Try "flash hard drive" or "NAND".

Flash hard drives are indeed coming out in the next couple of years. Samsung has announced one that I know of. At first we're likely to see hybrid disc/flash drives that will, as you say, use limited flash memory to decrease boot times, and good old magnetic platters to store most data.

There is nothing special about flash memory that I know of that has kept it from taking over from standard HDDs. It is simply the old issue of new technologies taking a while to catch up with and replace older technologies.
posted by Hildago at 5:50 PM on April 13, 2006

Uh, hybrid drives are coming. Why they're not here now: expense and flash memory has a limited number of write cycles.
posted by jellicle at 5:50 PM on April 13, 2006

The challenge is that flash doesn't survive as many read/write cycles as does a hard drive. Once you get that solved, and prices grow approach parity, you might get what you're looking for.

(I learned this by reading stuff. I am not an engineer.)
posted by Kwantsar at 5:50 PM on April 13, 2006

One of the problems (IMO) is that while drive space has gone up and up, the amount of space needed for an OS has gone way up as well. A default windows XP install is a couple gigs, it seems like. Windows 95 fit in a few hundred megabytes. Linux distros are the same way, they include a ton of crap, several gigabytes worth.

That said, you can get large flash drives that work as IDE drives you can boot a computer off of, but they're very expensive compared to regular hard drives.

here is some info I googled up about booting from USB thumbdrives. If your BIOS can boot from USB it's not going to care whether the drive you boot from is USB or flash.

here is an SATA flash drive that should be bootable in any modern PC.
posted by delmoi at 5:51 PM on April 13, 2006

As far as the read-write thing, you could just disable virtual memory on the system. If you have enough money to boot off of a flash disk, you have enough for 4gb of RAM, as well.
posted by delmoi at 5:53 PM on April 13, 2006

As soon as flash becomes cheap enough, it's certainly going to happen. Microsoft is already encouraging hard drive manufacturers to make "hybrid" drives which combine flash and conventional technology to make extremely well-cached drives. Samsung has already announced a HDD killer 32GB flash device.

It's not uncommon even today for OSes to be put on flash drives - this has been going on in embedded devices for at least five years (see Advantech devices, for example). It's quite possible on most modern motherboards to boot from USB, so you could do actually do this right now.

One thing that you should keep in mind is that flash memory isn't quite as fast as you assume it is in your question. And it typically doesn't support as many read/write cycles as hard drives (although both speed and durability of flash have been increasing).

A huge component of startup time in computers is waiting for devices to initialize and respond (cd/dvd drive, video, sound, etc). Flash may cut boot time by 1/2 or so, but it's not going to be as if everything were loaded in RAM.
posted by helios at 5:54 PM on April 13, 2006

ironmouth, not to derail, but a similar kind of mobile computing already exists with Sun Microsystems Sun Rays.
posted by j at 6:00 PM on April 13, 2006

j: "ironmouth, not to derail, but a similar kind of mobile computing already exists with Sun Microsystems Sun Rays."

Not really. Sun Rays and other thin clients simply present a graphic display of a session hosted on a large server (technically just a cheap X server with an E450 in the background). The cards were merely smart cards, not FLASH cards, that served as login and auth credentials. The only similarity in the cards is that they are both cards.
posted by kcm at 6:05 PM on April 13, 2006

A different point: even if the external storage device on a computer was infinitely fast, the computer still wouldn't boot up "instantly". There's a lot more going on during the boot process than just loading stuff from mass storage into RAM.
posted by Steven C. Den Beste at 6:13 PM on April 13, 2006

the bottom line rules here. when you can pack more bits per buck on a flash chip than you can on a drive platter, that's when you can expect to see HDD-less computers in stores near you. no sooner, no later. that said, there is a LOT of research in this area these days, and i guess i'd expect to see them something like 5-7 years off.
posted by sergeant sandwich at 6:20 PM on April 13, 2006

The flash drive install of DamnSmall Linux(50MB) does pretty much what you want now - Boots are zippy on 1ghz+ systems, and it loads completely to memory on ones with over 640mb RAM - I used to use it quite regularly when I wanted to use my wife's WinXP Vaio for stuff (CD Ripping/MP3 encoding) without larding it down with software she'd never use.
posted by Orb2069 at 6:38 PM on April 13, 2006

Here is a relevant article which goes into a few of the pros and cons.
posted by pompomtom at 6:42 PM on April 13, 2006

IEEE Spectrum says flash-based hard drives are "too little, too soon".
posted by GuyZero at 7:05 PM on April 13, 2006

Damn Small Linux is 50 megs, and can boot from a "business-card" CD or (some) thumb drives (on some PCs).

I've never used a thumb-drive Linux, but I have used some CD-based linux distributions. They offer the full range of applications, but the applications are generally slow to start. Generally, an option to store files and settings on the local drive or on a thumb drive is available.

There may be a way to make XP run from a thumb drive, but I don't have any first-hand experience here.

One problem with trying to boot the same operating system on different PCs is that they all have slightly different hardware. This means that sometimes you get degraded performance by using a generic driver (e.g., VESA for video cards) or sometimes it won't work at all (e.g., that wireless chipset that is unique to certain Dell laptops). Surprisingly enough, Linux is probably better for this than XP, because if it'll work with Linux at all, the driver is usually included already.
posted by jepler at 7:07 PM on April 13, 2006

orb: dangit, you posted half an hour before me, but I'd swear I didn't see you when I read through the earlier answers!
posted by jepler at 7:07 PM on April 13, 2006

One of the reasons they haven't done that yet is because all flash memory will only survive a limited number of write cycles.

For normal usage, that's not usually too critical, because the computer usually isn't writing _that_ heavily... the NAND circuitry is able to transparently map out failing sectors (they don't fail until they're written to), and they have wear-leveling algorithms, so they'll last a really long time.

The problem is.... swap space. When you overcommit your RAM, that is, you run more programs than you have room for, the computer swaps out inactive programs to disk, and then swaps them back in when they need to run. This is extremely disk-intensive, and will wear out a flash very, very quickly.. in very heavy use, most flash drives would only survive a couple of months before seizing up and dying.

Either operating systems need to be redesigned (which would be a good idea... accessing flash memory as a disk device is ultimately kind of silly), or flash drives will need some way of identifying and storing truly transient data without killing themselves.
posted by Malor at 7:10 PM on April 13, 2006

has anyone mentioned Samsung's prototype flash drive laptop that was a big story a few weeks ago yet?

if not, i just did.
posted by ab3 at 7:16 PM on April 13, 2006

What everyone else has said - it's worth emphasising that you can do this very easily with Damn Small Linux and a 128MB USB stick.

I'm running an entirely flash-based home server using a CF card and CF -> IDE adaptor. Storage is provided by a 1GB stick. Mini-ITX + external power supply + CF drive = totally slient machine. Sweet.
posted by blag at 7:18 PM on April 13, 2006

As far as the flash drives wearing out problem, the problem isn't really as bad as it initially seems. The durability of flash drives has increased dramatically over the last few years. It's to the point where you can absolutely use them for stuff that is rarely over written (like the OS).

In practice the only time there's even an issue is when an application overwrites the same file all the time. This can be mitigated by not writing the application that way, by caching writes in memory for longer before putting them on disk and by using a special filesystem that avoids repeated writes. There's a bunch of stuff about that in the Wikipedia article.
posted by joegester at 7:31 PM on April 13, 2006

With the rise of flash drive technology, it makes me wonder why flash drives can't be used as primary hard drives in computers/mp3 players/ handheld gaming devices, etc.

(Bolding mine.) Even with all the potential problems listed above, the iPod Nano is already here and using flash. It seems like the only obstacle in that area is price. Once a given size flash size is cheap enough, Apple will invariably switch to it over a physical hard drive.
posted by smackfu at 7:36 AM on April 14, 2006

Gosh, I had one of these in the early 90s, a Tandy 1110FD with the OS (DOS 3.3x) on ROM. Everything old is new again.
posted by m@ at 7:58 AM on April 14, 2006

no-one seems to have mentioned this, but i thought the mit "developing country" $100 (or wahtever) laptop was doing this.
posted by andrew cooke at 11:05 AM on April 14, 2006

Good question. Imagine generic workstations everywhere, and everyone just carries around the same flash drive and plugs it in wherever they go. The ultimate in mobile computing. Expect it to happen. - Ironmouth

I actually know a fellow at a company that is doing exactly that, the target market being hospitals. The NSA has also expressed an interest.
posted by phrontist at 12:40 PM on April 14, 2006

joegester writes "In practice the only time there's even an issue is when an application overwrites the same file all the time. This can be mitigated by not writing the application that way, by caching writes in memory for longer before putting them on disk and by using a special filesystem that avoids repeated writes."

We see this a lot with our students using Autodesk products. Despite warnings they open AutoCAD files directly off their flash devices and then proceed to work on them for the next five hours. AutoCAD writes to a log file and crash recovery file on most object inserts and manipulations. Plus it does an auto save every 5 minutes for every file that is open. Lots of the drives don't last the semester.
posted by Mitheral at 1:58 PM on April 14, 2006