Thursday, April 14, 2005

What's in a name?

I was recently confronted by yottabytes. And not just one, but four!

The prefix yotta was unknown to me prior to this confrontation, but I really wasn't surprised to have it come up simply because of the rapid expansion of capacities in the realm of computers. To give some background, in the late '80s my employer was considering the purchase of a new supercomputer. The max disk configuration was 300 and something gigabytes. And when someone whined about that being too small they were told that if they would buy the disk (from that vendor) they could have the supercomputer for free (roughly a $10,000,000 value). And I think they would paint it any color you wanted. (No, it wasn't Cray.)

Today you can buy a 400GB disk for $300. And hold it in your hand. You can buy a terabyte NAS box for $1000. I've heard that large companies are buying storage by the petabyte (actually, I heard that about 3 years ago — I shudder to think what they're buying now).

So back to yottabytes... how much is that? Well, it depends. Are you a decimal person or a binary person?
bad joke alert! There are 10 kinds of people on this earth: those who understand binary and those who don't.
An example: a million dollars is $1,000,000 but a megabyte of computer memory is typically understood to be 1,048,576 bytes. That's because computers are generally binary devices — everything is either a zero or a one. If you use the binary number system then it is often easier to let the prefix "kilo" represent 1024 instead of 1000. It then follows that mega is 1024 kilos, and so on.

But not all computer things are counted using the binary version. Case in point: disk drives. Disk drive capacities are listed using the decimal interpretations of the the metric prefixes. Computer geeks often refer to these values derisively as "marketing megabytes" (or marketing gigabytes), to imply that they are misleading. So geeks must love the recordable/rewritable CD market, because those capacities are actually decimal megabytes/gigabytes, but it can be difficult to know that.

The International Electrotechnical Commission tried to address this several years ago by proposing that the metric prefixes always

AAAARRRRGGGGGH! This crappy software just ate a bunch of my hard work! I give up!

1 comment:

Gene said...

I have learned to deal with the seemingly random nature of Blogger pharts, so I've been known (!) to edit my post locally, then cuttinpaste it to Blogger's editor at the precise moment in time when it will be stable.

I noticed a curious thing in Blogger's editor tonight: a new item marked [Recover Post]. Although my first instinct tells me this should have nothing to do with reupholstery, I am leery. Why would anyone editing a blog give a phart about putting a new covering on a cylinder?

There are some things that baffle me everyday, and this just adds to the list.

BTW, there's no truth to the rumor that a disc array capable of storing multiple petabytes is called a PetaFiler (even though you can search OneStop for this term, well .. at least through May 2004).