Memory is random access - RAM -
in that any location (or cell) can be accessed in the same
amount of time. (Click here for a description of RAM) Other memory organizations can include serial (usually on magnetic tape), or rotating (drums, disks).
Each memory location has
an address and contents (typically one byte, where
a byte is 8 bits).
A memory access is a read
(fetch) or a write (store).
If N bits are used
to represent the address of a memory location, then the (virtual) address
space is 2N bytes.
= 32 then the address space is 232 = 22 ·
230 = 4 GB (gigabyte).