Hard Drives

In 1956, a little more than fifty years ago, IBM introduced the world’s first hard disk drive: the IBM 350 disk storage unit. Its 50 magnetic platters had a storage capacity of five million characters (5 megabytes). That’s not 5 MB per platter; it’s 5 MB for the entire unit. The 350 was 60 inches (152.4 cm) long, 68 inches (172.7 cm) high and 29 inches (73.7 cm) deep – about the size of a double-wide fridge. Its electronics used vacuum tubes, of course. The read-write heads were positioned by pneumatic controls, so the unit also contained a small air compressor.

 

 

 

 

Fast forward a half century to 2011 and we have hard drives that can fit on a fingertip and store vastly more than the IBM 350 could store. The image at right shows a Toshiba 0.85 inch hard drive with a capacity of 4 gigabytes; that’s 4 thousand million bytes.

Hard drive storage has increased 40% per year since the introduction of the device. Today, a 2 TB (terabyte) drive for your desktop PC sells for $80. Two terabytes is two thousand gigabytes and two million megabytes! In fifty years hard drives have gone from a few megabytes to a few terabytes capacity (one million times greater) and have shrunk from 60 inches wide to less than an inch wide.

Kilobytes … megabytes … gigabytes … terabytes … each prefix is one thousand times greater than the preceding prefix. What’s next and when will we get there?

In 20 years we’ll have exabyte drives. An exabyte is one thousand terabytes.

In 40 years we’ll have zettabyte drives. A zettabyte is 1000 exabytes.

In 60 years, cheap consumer hard drives will be measured in yottabytes. A yottabyte is one thousand zettabytes.

The International System of Units has no prefix beyond yotta, so I’ll have to invent a prefix for what hard drive capacities will be in 80 years. Of course, the prefix can be only one thing (and you had to see this coming). It will be … yotta-yotta.