20 April—Had Hitler not offed himself in his Führerbunker on 30 April 1945, he’d be 134 today. And, although it wasn’t about Hitler, not a single Monitor reader caught the obvious error in 17 April’s “Let the cloud roll by.” Perhaps you all were too polite to point it out. It’s since been corrected in all events, so you don’t need a link to my embarrassment.

I wrote, “My current computer has one-and-a-half gigabytes of solid-state disc (sorry, disk) storage built in, [yotta yotta yotta].” One-and-a-half gigabytes? Twenty-year-old USB 2.0 thumb drives have more than that. What was I thinking? Was I thinking? Of course I meant terabytes. What can I say?

Anyway, my embarrassing lapse got me thinking (which happens less and less of late, thoughts being inversely proportional to age), what’s the difference between gigabytes and terabytes in digital storage anyway? As well as all the other bits and bytes. Hint: It’s all about orders of magnitude and mostly in the prefixes, as well as convenience and convention. So here’s a primer on binary prefixes and prefix multipliers:

Bits first. A bit—short for binary digit—is the smallest unit of data that a computer can process and store; it’s always in one of two physical states, off or on. The state is represented by a single binary value, usually 0 or 1.

In the modern digital world, 8 bits make 1 byte. Almost always, but don’t worry. Don’t worry about kilobytes, either. A kilobyte, from Greek kilo- meaning thousand, should be 1,000 bytes. But since computers use the binary (base-2 numbering) system, the base-2 number nearest to 1,000 is 1,024. That’s why in digital computing, 1,024 is referred to as “kilo-,” giving us 1,024 bytes in a kilobyte (kB).

Convenience and convention continue from there:

1,024 kilobytes=1 megabyte (MB) (from Greek mega- meaning great or huge);

1,024 megabytes=1 gigabyte (GB) (from Greek giga- meaning giant);

1,024 gigabytes=1 terabyte (TB) (from Greek tera- meaning monster).

Now for grown-up computing:

1,024 terabytes=1 petabyte (PB) (starting here, prefixes not necessarily from Greek);

1,024 petabytes=1exabyte (EB);

1,024 exabytes=1 zettabyte (ZB) (possibly from the Greek letter zeta);

1,024 zettabytes=1 yottabyte (YB) (possibly from the Greek letter iota).

The yottabyte is the largest unit approved as a standard size by the International System of Units (SI). The yottabyte is about 1 septillion bytes—or, as an integer, 1,000,000,000,000,000,000,000,000 bytes. The storage volume is equivalent to a quadrillion gigabytes or a million trillion megabytes. Written out, an actual yottabyte would be 2 to the 80^th power or 208,925,819,614,629,174,706,176 bytes. You can take that as gospel.

Currently, there’s nothing that can be measured on a yottabyte scale. But one source reckons that by the end of 2030 the world will have generated 1,000 zettabytes, thus entering the age of yottabyte. But don’t be surprised if it should come sooner. Yotta yotta yotta indeed.

To complicate matters, when the digital crowd theorizes or fantasizes above yottabytes, the nomenclature is at best totally informal. For instance, in one system, 1,024 yottabytes=1 brontobyte (from the Greek meaning thunder); 1,024 brontobytes=1 geobyte (from the Greek meaning earth); 1,024 geobytes=1 saganbyte (from the late popular astronomer who wasn’t Greek), and so on.

To bring those figures into graphic gastronomic perspective, if not great exactitude, one source started with a grain of rice representing one byte, neglecting to specify raw or cooked. Then a kilobyte was an undefined cupful; a megabyte was eight undefined bags; a gigabyte filled three unspecified semi-trucks; a terabyte filled two container ships of unstated capacity; a petabyte covered Manhattan Island with a layer of unspecified thickness; an exabyte covered the undefined left coast with an equally inexact layer; a zettabyte filled the Pacific Ocean to some degree; and a yottabyte made a ball of rice the size of the Earth.

You can take that with a squirt of soy sauce. But it’s something to think about . . .