Has anyone installed a solid state flash drive?

January 5, 2007 11:07 PM

I've got an older notebook, and I was thinking it would be an interesting project to replace its 2.5" hard drive with a solid state flash drive. I'd probably just go with a 4 GB drive, and keep all my data out on the Internet. I was thinking it would extend the battery life, speed up data access, and make the machine a little quieter. Has anybody done this?
posted by fcain to computers & internet (17 comments total)

I've been using a Palm LifeDrive as my PDA for the past year or so. In case you're not familiar with the model, it's basically a Palm OS 5 device with a 4GB hard drive.

Some users of the LifeDrive have replaced the internal hard drive with a 4GB flash card.

Not precisely what you're asking for (Notebook vs. PDA), but perhaps it will give you some insight into how they went about researching and resolving the issues involved.
posted by Mutant at 12:22 AM on January 6, 2007

Here's a (single point) of interesting data about laptop power usage.

Seems the hard drive uses slightly more power than the WiFi, so your power saving would probably be minimal (unless you leave the wiFi connected all the time anyway)

And keeping all your data on the internet would drastically slow down access (net access speeds vs hard drive access speeds). Only launching applications would be (potentially) faster.

However a solid state hard drive does get rid of the component most likely to fail in your computer, and a significant source of heat generation. Just make sure you use solid state memory rated for hard drive use or you'll get failures pretty quickly.

All in all I think the benefits will be low, but it sounds like a fun experiment.
posted by Ookseer at 12:40 AM on January 6, 2007

But flash memory is really, really slow. Even the most expensive compact flash cards can't beat the transfer rate of a laptop disk. Flash also takes a huge performance hit when operating on small blocks, just like disks. Although it's a silicon device, flash characteristics are closer to those of disks than RAM (except for price). Also, your disk has several megs of cache and CF cards have none.

Seriously, this is a bad idea.
posted by ryanrs at 1:42 AM on January 6, 2007

What about when the OS starts swapping to the disk? Doesn't that wear away the flash memory's write cycles?

I always assumed with solid state drives, you still needed a regular hard drive for the pagefile -- the OS would be aware of the flash, and keep only (generally) read-only files that it needs -- in Windows' case, all the main shared DLLs and executables.
posted by spiderskull at 1:50 AM on January 6, 2007

Swapping sucks regardless of storage type. If you're swapping to flash, capacity may be a bigger worry than finite write cycles.
posted by ryanrs at 1:59 AM on January 6, 2007

ryars: It's not that bad. Sure, flash transfer rates are slower than discs, but they have zero seek time for random reads (for obvious reasons!) so on a lot of workloads flash can be faster than disc.

And while CF write speeds are slower than current discs, we're talking about a factor of 2-5 times slower, not orders of magnitude slower. That's compared to current standard PC hard drives: the hard drive in an old laptop might well have be matched in raw write speed by currently available compact flash cards.
posted by pharm at 2:08 AM on January 6, 2007

Nb. I wouldn't swap to flash if I could help it though.
posted by pharm at 2:14 AM on January 6, 2007

But since disks completely blow for random reads, we've spent the last 30 years making sure they never happen. So you can make random reads as fast as you want but most users won't notice. See Amdahl's Law.

Anyway, what's the point of this nonsense? Flash is slower, smaller, and pricier than disk. Both use very little power and both are pretty reliable. You'll still need backups to protect against theft, deletion, and viruses. Of course with flash a full system backup will fit on a single DVD. There's an advantage, I guess.
posted by ryanrs at 3:49 AM on January 6, 2007

"...And keeping all your data on the internet would drastically slow down access ..."

Not to derail, I just wanted to point out that OP didn't mention what data would be stored on the internet.

I've got two G3 Clamshell iBooks that I effectively use as thin clients. Everything lives on .Mac, Google or my own server, and Firefox is the only app installed on the machines that is regularly used.

So I could imagine a fairly useful flash based machine. I dumped my Emate years ago, but that little box worked very well for writing.
posted by Mutant at 4:25 AM on January 6, 2007

Sandisk just announced a "solid-state drive" of 32 GB. Pricey, yes, but they're claiming it is fast, and presumably they've worked out the rewrite-limit problem.

I have no experience with these, but I suspect it's the way things are headed for laptops.
posted by adamrice at 7:12 AM on January 6, 2007 [1 favorite has favorites]

I really just use the laptop for web browsing. My email's through Gmail. Google docs and spreadsheets, etc. I've been running Ubuntu, and I'm only using 2.5 GB of space on a 20 GB drive.

After reading through the Palm Lifedrive discussions, people said the performance was much zippier when the made CF drives, the device produced less heat, and the battery life was greatly improved.
posted by fcain at 7:20 AM on January 6, 2007

Remember flash drives most likely have a shorter lifespan than the average hard drive. They have a limited number of writes you can perform before they start malfunctioning and corrupting the data. It's hard to predict exactly when this will happen, some devices will fail after hundreds of thousands of writes, others after a million writes. Typically, if someone is running an operating system off a flash device, the OS will be heavily modified to cache or eliminate as many writes as possible.
posted by knave at 7:32 AM on January 6, 2007

That SanDisk is somewhat faster than laptop disks, but the difference is not as large as the press release implies. The press release compares the flash disk to a 4200 rpm 1.8 inch disk—an iPod disk. Laptops use 2.5 inch disks running at 5400 or 7200 rpm. A high-end laptop disk will achieve similar transfer rates as the flash disk. In regard to the other specs, the flash disk wins on power and access time, but loses on capacity and price (about $600).
posted by ryanrs at 9:26 AM on January 6, 2007

I've done exactly this with a mini-ITX machine that I use as a home server. I swapped out the 2.5" notebook drive for the following combination:
- 2GB Compact Flash card (£20)
- CF-to-IDE adaptor (£5)
- 3.5" IDE to 2.5" notebook cable (£4)

OK, so its not a true solid state drive but, for all intents and purposes, it works in exactly the same way.

The main benefit is the reduced heat and noise. Since the mini-ITX motherboard is fanless, the only noise coming from the machine was the high-pitched squeal produced by the laptop drive. Replacing this with a CF card has made the machine completely silent. Like, spooky quiet. The only way to check it's running is to ping it.

Boot time is slightly slower (67 seconds vs 44 seconds, yeah I timed it...) but since I'm running it as a server I only reboot every few months. Once everything is up and running, there is no noticeable difference between the drives.

I also use a 2GB USB pen drive as a storage drive, making it easy to take the 'hard disc' with me if I need anything stored on the server.
posted by blag at 9:27 AM on January 6, 2007 [1 favorite has favorites]

The Lifedrive guys are noticing an improvement compared to their original IBM microdrives. Microdrives are much slower than laptop disks. Also, the power savings from switching to flash will be much more noticeable on a PDA than on a laptop. The laptop's faster processor and larger, brighter screen dominate the power budget and make the disk comparatively less important.
posted by ryanrs at 9:38 AM on January 6, 2007

I'm sorry I don't have more specifics, but since it hasn't been discussed yet I'll mention it.

There are many forays into portable versions of programs like firefox that can exist just on a flash thumb drive. Likewise, many scaled down OSs can be booted from a thumb drive or a CD without the need for a hard drive. In that case, the OS makes due without a page file and keeps the booted OS and files just in ram. I've even heard that OSes on a CD-RW can store files to the CD as if it were just a HD.

Of course, these would have their advantages and disadvantages. A small OS might be faster, but less flexible. Personally I think it would be a fun project. Check out the wiki!
posted by cowbellemoo at 10:58 AM on January 6, 2007

Samsung, for one, has done this. And they've come up with an even better way.

I so lust after the silent machines that'll be possible when these get cheap enough for my budget...
posted by Zed_Lopez at 11:23 PM on January 6, 2007