Memory is the workspace for the computer’s processor. It is
a temporary storage area where the program and data are being operated.
Main Memory is divided into two: RAM AND ROM
RAM means Random Access Memory which allow you to randomly and
quickly access any location in memory.
There are three types of physical memory used in moderns
PCS, they are:
ROM: Read only memory
is a type of memory that can permanently or semi-semi permanently hold data.it
is thus called because any data stored in it will remained even if the power is
turned off. Moreover it is difficult or impossible to write to. The motherboard Rom normally contains four
main program including the following in most systems.
·
POST: POWER
ON SELF TEST Is a series of test routines
that ensure the system components are operating normally .
·
CMOS SETUP INFORMATION: A Menu driver application that
allows the user to set system configuration parameters, options,
security settings and parameters.
·
BIOS: (BASIC INPUT/OUTPUT SYSTEM): A series
of devices driver programs designed to
present a standard interface to the basic system hardware, especially hardware
that must be active during the booting process.
ROM chips are very slow by nature with the normal access
time of 150 ns compared to DRAM access time of
60ns or less BK of this, during operation, the content of RAM are
shadowed (i.e copied) enhancement and is
useful mostly if you are running 16-bit operating system like DOS or Windows
3.X but in 32-bit OS like Win98, shadowing is useless.
Four different types of ROM are:-
·
ROM (Read
Only Memory)
·
PROM
(Programmable ROM) also called flash ROM
·
EPROM (Erasable
ROM)
·
EEPROM (Electrical
Erasable ROM)
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