Atari XL - Page 237

APPENDIX 4
NUMBERING SYSTEMS
Computers store and operate upon numbers in a
different way from humans - they use a numbering
system known as binary notation.
Binary notation is a means of representing
quantities with groups of Is and Os. We are more
used to a system called decimal notation, in which
quantities can be represented by combinations of
up to ten symbols (the numbers 0 to 9).
Computers use the binary system because they are
able to recognise and differentiate between only
two states - ON and OFF. These two states can
conveniently be represented by 1 (ON) and 0 (OFF).
A single 1 or 0 is called a BInary digiT, or BIT, and
computers store data in the form of groups of eight
of these bits, known as BYTES.
In the computer memory, one memory location is
able to store one Byte of data (eight bits). A
collection of 1024 of these bytes is called a
KILOBYTE, or k for short. We can get an idea of
the data storage capacity of a computer from the
number ofk of memory it has (48k, for example, is
48 * 1024 * 8 bits).
We have described a byte as a collection of eight
bi ts, like this:
11111111
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