One GB JetFlash Memory Sticks - A Finite Life?

[UNCTUOUS]

Was given a one GB USB JetFlash Memory Stick and, not knowing anything about them, decided to look them up on the net at this link.

I was surprised to see that they are "lifed" at one million writes (or "erase cycles") - so I was so pleased that I hadn't made it my Win XP standalone swap file disk.

Does anybody know whether this is limit is a hard limit or

a. whether it's just when you could expect planned design obsolescence to cut in or

b. That's when the itty bitty battery that keeps the RAM powered cannot any longer take and hold a charge?

I realize that they are intended to just transfer data between /via USB ports on compliant machines however at the rate I would normally "write" to a hard disk, that one million cycles would be a life of about six months max.

Maybe somebody out there knows better. One puzzling thing is that even though these devices are just memory sticks, they don't seem to be all that fast (nowhere as fast as a ram disk for instance).

[Fujiflyer]

UNCTUOUS

I don't think they use battery backed RAM, rather I think they use a type of memory called EEPROM (E2ROM, - electrically erasable read only memory) which is inherently non-volatile (retains memory without power applied). However this type of memory has limited write cycle capability as you have seen. It is something to do with electric field stress during programming. This value is typical for an EEPROM device. Incidentally there is a similar type usually just called Flash used to hold microcontroller program code which is rated at only about a thousand cycles as it is not expected to have to be rewritten so often.

FujiF

[Mac the Knife]

'Scuse me UNCTUOUS but why on earth would you want to use a slow device like a memory stick as the XP swapfile? It's an order of magnitude slower than a normal hard drive and 2 orders slower than RAM !

EEPROM's do have a limited cycle life, but in normal practice (just using it to carry files around) you probably would'nt see it before the device itself is obsolete. If you use it as a (very slow) swapfile with constant reads/writes of course you'll see it's end-of-life sooner.

XP, left to it's own devices, handles it's swapfile quite intelligently for RAM <512MB. If you have more than that it's best to limit it to 512MB, remembering that the more memory you have the less your swapfile will be used.

From Fastest to Slowest, these are the configuration you can try:

No swap file at all. Need at least 512MB RAM. Some software may fail.
A static swap file on a separate hard drive (and preferably, controller)
A dynamic swap file on a separate hard drive (and preferably, controller)
A static swap file on a separate partition, but on the same physical hard drive as Windows.
A dynamic swap file on a separate partition, but on the same physical hard drive as Windows.
The Default: A dynamic swap file on the same partition and physical hard drive (usually C:) as Windows.
Slowest of all - memory stick. Windows may stall.

[Ausatco]

Thanks for that list, Mac. I'm changing my two PCs right now.

If one has the choice of and NTFS or FAT32 partition for the swap file, which is faster?

I've heard FAT32 is, but not sure of the source.

Cheers

AA

[25F]

Fujiflyer,
http://www.drix.be/types.htm describes different memory types. Flash (which was originally a trade name) is a type of EEPROM, and it's that which is used in USB memory sticks and the like. The site also explains why some types of memory are faster than others.

Ausatco, this site agrees on FAT32:
http://www.tek-tips.com/gfaqs.cfm/pid/96/fid/3876,but I reckon if you're worried about a small difference in swap-file speed you need more RAM...

[Ausatco]

Nahh... just looking for getting the best out of a tweak. It's neither here nor there really. Both machines are P4s with XP Home and 512 meg RAM and both perform OK. Just fiddling to see what happens.

AA

[Mac the Knife]

FAT-16 is theoretically fastest because it involves the least seeks (the FAT entries are 2 bytes rather than 4 and the FAT itself is potentially smaller). You're limited to 2gb but so what - a 1gb swapfile is more than enough if you have >256mb RAM. You may have to tinker with the cluster size to get the best performance - the 32K default for 1gb is too big so try 8 or 16K (though the FAT gets bigger).

Make it permanent by setting the MIN and Max values the same - that way it won't fragment.

Resist the temptation to use that old 1gb drive that's sitting in the spares drawer - it'll almost certainly be too slow.

If you have only one controller but plan to use a separate HDD for your swapfile then put it on the secondary IDE channel as master.

With 512mb of RAM the swapfile is used very little and with 1gb hardly ever - it may not be worth all these shenanigans.

So technically the best bet for the average punter with >256MB RAM is a 1gb FAT-16 partition on the primary drive.

Must confess I don't bother......

[Ausatco]

Thanks again, MtK. I do a fair bit of photo editing involving large files. More memory would probably be appropriate for sustained blistering performance, but in the mean time efficient virtual memory is also appropriate.

I'll play around with some large files and see what happens. If there's only milliseconds in it, then I suppose it's all a bit theoretical, isn't it?

AA