Digital Bits and Bytes

Posted By BrokenClaw on September 8, 2007

Computers are digital. Everything they do has to be converted to a digital description. The discrete element they use is called a bit. It is typically described as off or on, down or up, negative or positive. In text, a bit is denoted by 0 or 1. There is no in-between.

Since this system uses only two elements, it is called a binary system. In fact, the term bit is a contraction of binary digit. Bits are useful because they can be stored and transferred in various forms: electronically on a chip or through a wire, magnetically on a hard disk, or physically on a CD or DVD.

Putting a few bits together you make a byte. One byte is sufficient to describe a letter of the alphabet. For example, the byte 1100001 represents the small letter a. Every computer knows that when it reads 1100001, it should display the letter a on the screen. And every computer knows that when you press the A on your keyboard, it stores that signal as 1100001, unless you are typing caps, and then it stores 1000001. Computer technology can read and write bits and bytes at mind-numbing speed. Your computer can read an entire novel, like Gone With the Wind or War and Peace, from the hard drive in a fraction of a second.

The digital code for the letters of the alphabet has been around a long time, known as the American Standard Code for Information Interchange (abbreviated ASCII and usually pronounced ask-ee).

It may seem that 1100001 is more complicated than one little a, but it is tremendously more efficient. Think about your ten fingers. You can hold up your fingers and display any number from zero to ten. Fine. But if you use your digits (yes, that’s where the word comes from) to represent bits in sequence, where each finger means 1 when it’s up or zero when it’s down, you can display every binary number combination from 0000000000 to 1111111111, which is one thousand twenty-three!

The byte is the standard unit of computer information, but most things are described in terms of a kilobyte, abbreviated k or kb, which is one thousand bytes. One thousand kilobytes make a megabyte, abbreviated MB, and one thousand megabytes makes a gigabyte, abbreviate GB, and one thousand gigabytes makes a terabyte, TB.

Some relative sizes:

  • a paragraph of a text message or email is a few kilobytes
  • a word processor file of several pages is a few hundred kilobytes
  • a quality photograph is about one megabyte
  • high quality music uses about 10 megabytes per minute
  • high quality video can be several megabytes per second
  • a standard audio CD holds about 600 megabytes, or 60 minutes of music
  • a standard DVD holds about 4 gigabytes, enough for a feature-length movie

Transfer speeds, with regard to moving files over a network, such as uploading and downloading, are sometimes expressed in terms of bits per second (bps) instead of bytes per second. It makes it look faster.

Read how Baseball is Digital, Football is Analog.

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