From C64-Wiki

A byte has got eight bits and is an unit of the information or storage capacity. This eight bits can be switched in 8 to the power of 2 wise (also 256 sorts of states). In a few computer systems, software or coding languages exists another or unexactly definition of bytes. Another fragmentation of Bytes are nibbles (this are 4 bits) or 2 half-byte.

The normal character set of a computer system consists of ASCII or ANSI, which has got 256 different chars. A byte can also content a char ("A" is the byte "01000001" or the decimal value 65).

[edit] Low- / High-Byte

In the 8-bit computer systems like the C64/C128 can get every memory adress any value from 0 between 255. That isn't enough for adressing for all the 65535 memory adresse of an 8-bit computer. Also the operation system use if required two bytes (16 bits). In which case the first byte is used as "low-byte" (for 0 until 255) and the second byte is used as "high-byte" (256 until 65280, in 256 steps). With this term low-byte + high-byte * 256 the programmer can be adressing the whole memory map from 0 until 65535.

[edit] Bytes units

• 1 Kilobyte (KB) are 1024 bytes
• 1 Megabyte (MB) are 1024 Kilobytes are 1024*1024 bytes
• 1 Gigabyte (GB) are 1024 Megabytes
• 1 Terabyte (TB) are 1024 Gigabytes
• 1 Petabyte (PB) are 1024 Terabytes

By more than 1024 bytes it is better to use the international prefixs. For disks the storage capacity is used in KBytes, whereas for CDs and harddisks are preferred in MBytes and higher storage media like DVD and actual harddisks are produced in GBytes.

[edit] Links

Wikipedia: Byte