# From bits to yottabytes. How much data is that?

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Being the storage editor, I'm often asked by colleagues what comes after what when it comes to data storage measurements. So for the record I thought I'd just put it out there. In doing so, it struck me that there was a time -- only a few years ago -- when a petabyte (1 million gigabytes) seemed an impossibly enormous amount of data that no one would ever need to store. I mean, the Library of Congress with 130 million items on about 530 miles of bookshelves, including 29 million book, 2.7 million recordings, 12 million photographs, 4.8 million maps, and 58 million manuscripts, can be stored on 10 terabytes (10,000 gigabytes). Now, of course, tape libraries in enterprises regularly store multiple petabytes of data and some disk-based storage sub-systems are also surpassing the petabyte mark in capacity. And so storage marches on, in most cases surpassing Moore's Law.

Last year, when Sony came out with its MicroVault Tiny, which stores 4GB (4 billion bytes) of encrypted data on a USB flash drive smaller than my thumbnail, I realized there are no longer any limits.

Randy Levine, founder of ZettaCore Inc., a developer of molecular memory technology, says five or so years out we can expect to see tens of billions of bytes (gigabytes) on a single mini-USB flash drive.

"It might be hard to imagine, but I remember when a 250 (kilobyte) disk was big,"  says Levine, who works in silicon using nanometer measurements. A nanometer is one-billionth of a meter.

For the fun of it, I keep an advertisement on the wall next to my desk that displays a 15 megabyte hard disk drive for the unbelievably low price of \$2,495. If you bought two, you'd get the second one for only \$1,995, the ad states. Today, you can buy a MicroVault Tiny drive with 4 gigabytes of capacity for \$120 list.

Anyhow, for those of you who care, here it is for the record:

1 Bit = one binary digit (represented by a 0 or a 1).

1 Byte = 8 Bits (or one text character)

1 Kilobyte = 1,000 Bytes

1 Megabyte = 1,000 Kilobytes

1 Gigabyte = 1,000 Megabytes

1 Terabyte = 1,000 Gigabytes

1 Petabyte = 1,000 Terabytes

1 Exabyte = 1,000 Petabytes

1 Zettabyte = 1,000 Exabytes

1 Yottabyte = 1,000 Zettabytes (a 1 followed by 24 zeros -- 1,000,000,000,000,000,000,000,000)

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