Wednesday, January 31, 2007

The Long and the Short of USB Storage

Key Drives, Memory Sticks, Flash Drives, whatever you want to call them, are the new floppy. Quick, simple to use they are by far the superior portable medium.

However, which one should you buy? Here is a short list of things you should look for when purchasing USB Flash Memory drives (in no particular order):

  1. Physical Shape -> Grab the plug of a USB device. That plug is a standard size. Try to buy a drive that has the same width and thickness as that plug. This will ensure that the drive plays nice in tightly packed areas. Larger drives may crowd other plugs or you may have to unplug stuff just to plug in your drive.

  2. Storage Capacity -> If you can afford it, get a minimum of 1 GB. 4 GB is a bit much, if you're moving lots of files or really big ones, get an external hard drive.

  3. Get High Speed USB (also called USB 2.0) -> Make sure the drive supports high speed transfer. Simply saying "compatible" doesn't mean much. USB 1.1 and USB 2.0 work together by design, the only issue is that you only get the high speed transfer rates when a high speed drive is plugged into a high speed socket. The speed difference is like night and day!

  4. Brand and Quality -> Stay away from no-name brand flash memory, especially if what you are storing on them is important. SanDisk and Verbatim are two good companies that I have used, but there are others. Since flash memory can only be written/erased 1 meeellion times (pinky to mouth) higher quality drives will distribute writing over the entire flash "area" so the drive ages equally. Higher quality drives last longer due to higher quality components and manufacturing.

  5. Moving Parts -> If you plan to be using the drive quite a bit, use a solid drive that utilizes a removable cap. New drives feature an extendable USB plug, but after a few hundred extensions/retractions the locking mechanism may wear out.

  6. U3 preinstalled software -> I bought a drive that has U3 installed on it. U3 is a system of installing software right on the drive so that you can run the software right off the drive no matter which computer you are using it on (only software from the U3 site can be installed). It has its own version of the "Start Menu" that launches when you insert the drive. I does this by exploiting the fact that all Windows computers automatically launch software on CDs upon insertion (horribly insecure, I will tackle this issue in a later post). The drive is actually two drives, part of it pretends to be a CD, the rest is the actual storage drive. I would avoid U3 if you can, otherwise the drive manufacturer may provide software to remove the U3 installation (I know SanDisk does).
While we are on the subject of storage, I had to get this little tidbit of information off of my chest. Ever notice that the storage capacity reported by the Operating system is less that what is on the box?

This is because the box is dividing by powers of 10 but should be dividing by powers of 2. Confused? Let me explain.

Computers do math with 1's and 0's, therefore everything is a power of 2. Thus a kilobyte is not 1000 bytes, it is 1024 bytes. Dividing by 1000 gives a bigger number than dividing by 1024 (about 8% when comparing gigabytes).

This brings me to my next issue kilo-, mega-, and giga- are SI (metric) prefixes and should not be used with computer units. The following table shows the proper terms compared with convensional terms:

Quantities of bytes
SI prefixesBinary prefixes




kilobyte (kB)103210kibibyte (KiB)210
megabyte (MB)106220mebibyte (MiB)220
gigabyte (GB)109230gibibyte (GiB)230
terabyte (TB)1012240tebibyte (TiB)240
petabyte (PB)1015250pebibyte (PiB)250
exabyte (EB)1018260exbibyte (EiB)260
zettabyte (ZB)1021270zebibyte (ZiB)270
yottabyte (YB)1024280yobibyte (YiB)280

Here is a table comparing reported vs actual size:

NameBin ÷ DecDec ÷ BinExamplePercentage difference
kilobyte : kibibyte1.0240.976100 kB ≅ 97.6 KiB+2.4% or −2.3%
megabyte : mebibyte1.0490.954100 MB ≅ 95.4 MiB+4.9% or −4.6%
gigabyte : gibibyte1.0740.931100 GB ≅ 93.1 GiB+7.4% or −6.9%
terabyte : tebibyte1.1000.909100 TB ≅ 90.9 TiB+10% or −9.1%
petabyte : pebibyte1.1260.888100 PB ≅ 88.8 PiB+12.6% or −11.2%
exabyte : exbibyte1.1530.867100 EB ≅ 86.7 EiB+15.3% or −13.3%
zettabyte : zebibyte1.1810.847100 ZB ≅ 84.7 ZiB+18.1% or −15.3%
yottabyte : yobibyte1.2090.827100 YB ≅ 82.7 YiB+20.9% or −17.3%

Now I know that is quite a bit to absorb, you may want to ponder it for a few days. Until next time, keep having fun.

"bah weep graaagnah wheep ni ni bong"


Sal said...

holy crap. you've answered a question about a topic I've always wondered about! So THAT'S why my iPod reports 27.x Gigs instead of the 30.

RadioFreeG said...

I agree with everything you said in the post, EXCEPT about the size of the USB. Both PHYSICAL and MEMORY wise. The physical size is not a problem at all if one invests $5.00 and buys an extension cable. I actually prefer this IF I am going from computer to computer, as I do at school, and the USB ports are not the cleanest ones around! I'd rather replace a cheap extension cable than my USB.

Speaking of which, everytime a computer geek starts off a sentence with, " 'X' is plenty of space/memory/riceballs...", I find they are full of crap. You know that as soon as you buy something the new version is on a truck making it's way to the store. 1 GIG of memory is ok, but that is not much more than a CD. 4 gig is about the size of a DVD, and that is the largest portable media going. (Exclude the dual layers as I don't know of anyone that uses them.)

So, we have a 4 GIG model available for a hundred bucks or so, and this should be the DEFAULT standard since computing requirements, much like inflation, will always trend to rising. If you need to carry more than you can fit on the biggest USB drive, then you need a portable hard disk drive, period.

(AND, the whole powers of 2/10 thing is great!)