what is RAM?

10:29 AM in computer hardware

Pronounced ramm, acronym
for random access memory, a type of computer memory that can be accessed randomly; that is, any byte of memory can be accessed
without touching the
preceding bytes. RAM is the
most common type of
memory found in computers and other devices , such as printers. There are two different types
of RAM: DRAM ( Dynamic Random Access Memory ) and SRAM ( Static Random Access Memory ). The two types differ in the technology
they use to hold data, with
DRAM being the more
common type. In terms of
speed, SRAM is faster. DRAM
needs to be refreshed thousands of times per second
while SRAM does not need to
be refreshed, which is what
makes it faster than DRAM.
DRAM supports access times
of about 60 nanoseconds, SRAM can give access times as
low as 10 nanoseconds.
Despite SRAM being faster, it's
not as commonly used as
DRAM because it's so much
more expensive. Both types of RAM are volatile, meaning
that they lose their contents
when the power is turned off. In common usage, the term
RAM is synonymous with main memory, the memory available to programs. For example, a computer with
8MB RAM has approximately 8
million bytes of memory that
programs can use. In contrast, ROM (read-only memory) refers to special memory used
to store programs that boot the computer and perform
diagnostics. Most personal computers have a small amount of ROM (a few
thousand bytes). In fact, both
types of memory (ROM and
RAM) allow random access. To be precise, therefore, RAM
should be referred to as read/
write RAM and ROM as read- only RAM. See the "DRAM Memory Guide" in the Quick Reference section of Webopedia. This
Webopedia Quick Reference
offers general information on
the two types of RAM and
provide an overview on the
common modules of each type.