When I went shopping the other day, I stepped into CompUSA looking to buy a few computer components. One of these was a hard drive. When I approached the rack, a salesperson came up to me and asked me how much space I thought I needed for my computer. I answered that I didn’t need much; I just wanted to get the cheapest hard drive on the shelf.
It turns out that the cheapest hard drive on the shelf was a 250 GB, 7200 RPM Maxtor drive with a 16 MB cache. It retailed at $159.99, was on sale for $139.99, and had an $80 mail-in-rebate to top it off. That’s a pretty great deal (and here’s another if you’re jealous).
The prices of storage media are continuing to decline, and it’s getting to the point where it’s practically impossible to use all of the space you can buy. Let’s take a moment and add it up. Say I didn’t buy one hard drive, but two. That would have been 500 gigabytes at a price tag of $120. Doubling that (if I bought four hard drives), I’d have 1,000 gigabytes or roughly one terabyte for a mere $240. Heck, I could buy myself two terabytes for under $500.
But just how big is a terabyte? According to A.P. Lawrence:
If you can read 1,000 words per minute, and did nothing but read 24 hours a day, 7 days a week, it would take you around 2,000 years to read a single terabyte of data. Your computer can’t read a terabyte all that quickly either. If it could sustain 100 megabytes per second, you need ten million seconds. Don’t hold your breath while you wait.
Right now, I have a 40 GB drive on this machine that’s getting close to full. If I backed it up to a terabyte drive, I could make 25 copies of it before I ran out of space.
The hairs on your head might number around a quarter million, so you’d need four million people to get a terabyte of hair strands. Limit the eligibility to middle aged men and you might need a few more.
Fine sand seems to represent large numbers in fairly small volumes, sometimes estimated at 10,000 grains per cubic centimeter. We’d need 100 million cubic centimeters to get a terabyte, which is bigger than I want to store in my back yard.
The point is that even a terabyte of data is a tremendous amount. It seems we really are getting awful close to “big enough” for personal storage, though “fast enough” is still a long way off.
So it seems that the limiting factor in the amount of information our technology can handle is how fast we can access and process this data, not how much data we can keep. I just think it’s humbling that something like computers, often believed to exist in a realm of their own (“cyberspace”) are still subject to the same immutable laws as the rest of the physical world.