Byte

A byte is a collection of eight bits (a binary value of 0 or 1) or two nybbles. A nybble is represented by single digit from 0 to F (sixteen numbers, thus hexadecimal). As such, bytes are represented by a two-digit number from 00 to FF (totalling 256 possible values).

There are two bytes in a word and four bytes in a double-word (or long word). Additionally, 1024 bytes make a kilobyte, 1024 kilobytes make a megabyte, 1024 megabytes make a gigabyte, 1024 gigabytes make a terabyte, etc.

Units

Bytes

• 1024 bytes = 1 KB (kilobyte)
• 1024 KB = 1 MB (megabyte)
• 1024 MB = 1 GB (gigabyte)
• 1024 GB = 1 TB (terabyte)

Bits

• 1024 bytes = 1 KBit (kilobit)
• 1024 KBits = 1 MBit (megabit)
• 1024 MBits = 1 GBit (gigabit)
• 1024 GBits = 1 TBit (terabit)

Conversion

• 8 bits = 1 byte
• 8 KBits = 1 KB (kilobyte)
• 8 MBits = 1 MB (megabyte)
• 8 GBits = 1 GB (gigabyte)
• 8 TBits = 1 TB (terabyte)

Examples

• Nybbles represent single pixels in Mega Drive graphics.
• Bytes represent ASCII characters.
• Words represent one color in a Mega Drive palette.
• Double-words are used as absolute pointers in Mega Drive programming.

Bandwidth

Bandwidth is the rate at which data is transferred, typically expressed in bytes per second:

• 1 KB/s = 1000 bytes/sec
• 1 MB/s = 1000 KB/s
• 1 GB/s = 1000 MB/s
• 1 TB/s = 1000 GB/s

Bandwidth (or bitrate) can also be expressed in bits per second:

• 1 Kbps = 1000 bits/sec
• 1 Mbps = 1000 Kbps
• 1 Gbps = 1000 Mbps
• 1 Tbps = 1000 Gbps