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Octal: Difference between revisions
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The octal number system was used widely in the Electronics and Computer Industry, as although digital electronics is based on gates with only two states and is therefore fundamentally binary, binary numbers can quickly become long and hard to transcribe without errors. Their octal equivalents are much shorter and easier to remember, and have a straight-forward way of conversion to/from binary.
The [http://en.wikipedia.org/wiki/Pdp-11 PDP-11]
[[Unix]] file system permissions have three sets (user, group, others) of three bit permissions (read, write, execute), which is naturally represented in octal.
The use of octal numbers has declined as most modern computers no longer base their word length on multiples of three bits, (they are based on multiples of four bits).▼
▲The use of octal numbers has declined as most modern computers no longer base their word length on multiples of three bits, (they are based on multiples of four bits, so [[hexadecimal]] is more widely used).
== Comparing counts from zero in different number systems ==
C.f. [[Common number base
Binary
Octal
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# Split a binary number into groups of three digits, counting from right to left.
# Pad the leftmost group of binary digits with zeros on their left if their are less than three digits.
# Use the following table to translate each group of
Binary digits
Octal equivalent digit
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