As the storage capacity and cost of computer hard drives continue to improve, it just amazes me how many bytes you can store for a reasonable cost. For example, you can purchase an external 1 terabyte drive for less than $150….which is probably a good thing, since downloading a few videos and your daily email will fill that up in no time.
This got me thinking about how megabyte and gigabyte have made it into everyday language. Even Grandma knows that you want lots of gigabytes in your hard drive. Expect terabyte to make it into dinner conversation shortly. These prefixes that help us handle humongoid numbers come from the International System of Units (SI).
When I first started out messing around with electronics as a kid, I had to get used to these units. Back then it was mostly kilohertz and megahertz, along with kilohm and megohm. Not too bad. Capacitance was in microfarads and picofarads. (There was this strange usage of micro-microfarad, which I eventually figured out was the same as picofarad.) I didn’t know a tera from a giga.
There are twenty SI prefixes listed on the NIST web page, including:
When we get to 1000 terabytes, that will equal a petabyte. I don’t think I’ve ever used peta to refer to any numerical value, and certainly not exa, zetta and yotta. I kind of like the sound of yotta, as I can hear myself saying “there’s a yotta bytes on that 5 yottabyte hard drive.”
On the low end, we some other prefixes to deal with:
I have often used the prefixes up to femto and might have said atto once or twice in my career, but never zepto or yocto. Isn’t zepto the name of one of the Marx brothers? I’ve noticed that nano has worked its way into dinner conversation, via terminology such as nanotechnology. I’ve even heard a few non-technical people say something like “that will last about a nanosecond.”
It seems that things are getting more numerous (bytes on hard drives) and smaller (width of a transistor element) at the same time. This stretches out the dynamic range that we end up dealing with, and not just related to technical fields.
We just seem to have a lot of stuff.
73, Bob K0NR