What is Computer Memory? How is it used?
A computer requires memory in order to run applications
(RAM/DRAM), handle basic functions (ROM), as well as process all
video functions (VRAM). It is vital to a computer to have memory
in order to process all of the commands that are entered either
physically or programatically.
Firmware is ROM (Read-Only Memory) that resides on the
motherboard (the main board in the computer that contains the
CPU, bus, and slots for the cards to be plugged in to). Firmware
stores basic command information in order for the motherboard to
communicate with the CPU. It is called firmware because it
resides on the motherboard and is never (practically) removed or
replaced. It is ROM, because it cannot be rewritten. This is
important as it is what allows the electronics of the
motherboard (ie. +/- 5V) to be translated into 0s and 1s for the
CPU.
RAM/DRAM (Random Access Memory/Dynamic RAM) is used to store
programs while they are running. Programs (applications) are
stored in RAM and presented to the user based on the user's
requests. The firmware/CPU will "page" the application into
RAM/DRAM as needed, so the more RAM/DRAM that you have the
better off you are. "Paging" is a feature that allows large
programs that don't fit into the RAM/DRAM available on the
motherboard to "page" in the necessary piece of the application
when it is needed. For example, if you have 512MB of RAM/DRAM
and the program that you are running is 1GB in size, only 1/2 of
the program can be stored at any given time, thus it will be
paged into memory (RAM/DRAM) as neede (this a very general way
of looking at RAM/DRAM, not to be taken literally). RAM/DRAM is
also used by the CPU to handle internal O/S (Operating System)
issues. RAM/DRAM is critical to the motherboard and the
operation of a computer. RAM/DRAM therefore is not ROM, as it
can be (and is) rewritten over and over again during the course
of a user's session on the computer.
The last form of memory that I want to discuss in this article
is VRAM (Video RAM). This generally is stored on a video card
that is plugged in to the motherboard (NOTE: more and more
motherboards are coming with VRAM installed on them so that you
don't need a special card for it). Basically VRAM is RAM
specifically for rendering graphics on a screen of some sort
(monitor, TV). VRAM is very important for you gamers out there.
The more VRAM that you have the faster the computer tends to be
able to render your graphics. If you are not using your computer
for gaming then VRAM is nominally necessary.
As we have seen from this article, ROM, RAM/DRAM, and VRAM all
have important roles to play in your computer's operation.
Without any one of these pieces, you will be hard pressed to
have a running computer.
Happy computing,