CJKV Information Processing, 2nd Edition

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Chapter 1: CJKV Information Processing Overview

using binary notation.

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As discussed previously, computers process bits, which have two

possible values. In the next section, you will learn that hexadecimal notation does, how-

ever, have distinct advantages when dealing with computers.

What Is an Octet?

We have already discussed the terms bits and bytes. But what about the term octet? At a

glance, you can tell it has something to do with the number eight. An octet represents

eight bits, and is thus an eight-bit byte, as opposed to a seven-bit one. is becomes con-

fusing when dealing with 16-bit encodings. Sixteen bits can be broken down into two

eight-bit bytes, or two octets. irty-two bits, likewise, can be broken down into four

eight-bit bytes, or four octets.

Given 16 bits in a row:

111111111

this string of bits can be broken down into two eight-bit units, specically octets (bytes):

111

111111

e rst eight-bit unit represents decimal 1 (64), and the second eight-bit unit repre-

sents decimal 95 (5). All 16 bits together as a single unit are usually equal to 25,695 in

decimal, or <645> in hexadecimal (it may be dierent depending on a computer’s specif-

ic architecture). Divide 25,695 by 256 to get the rst byte’s value as a decimal octet, which

results in 1 in this case; the remainder from this division is the value of the second byte,

which, in this ...