2.3. Byte Size

Memory sizes are measured in bytes. Size means how many bytes/bits of data a memory can hold.

As memory sizes often are millions or billions of bytes, we usually talk about kilobytes, megabytes, and gigabytes.

Unit	Amount	Approximately	Symbol
bit			b
byte	8 bits		B
kilobyte	1024 bytes	Thousand bytes	KB
megabyte	1024 kilobytes, 1 048 576 bytes	Million bytes	MB
gigabyte	1024 megabytes, 1 073 741 824 bytes	Billion bytes	GB

The exact sizes are so peculiar because computers prefer using sizes that are a power of two: numbers that you get by multiplying number two with itself several times. For example

2 × 2 × 2 = 8

like the eight bits, or

2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 = 1024

which is the number of bytes in a kilobyte.

Next: 2.4. Memory Management

2.2. Byte

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