Transcript module 1- 3.1 primary storage

Storage device
00:44:40
Primary storage
Computer memory
00:44:40
Type of internal memory
There are two type of
memory:
• RAM (Random Access Memory)
• ROM (Read Only Memory)
00:44:40
Internal memory (RAM)
It is used by the computer to store
programs and data that are currently
being used;
It is usually referred to as Computer’s
RAM (Random Access Memory);
It is also referred to as the Computer’s
Immediate Access Store (IAS)
00:44:40
Internal memory (RAM)
00:44:40
Internal memory (RAM)
Internal memory can not hold all the
data and programs that a computer
might need;
It only holds the data and programs that
are in use at a particular moment in
time, and empties and refills itself as
different programs and files are used
00:44:40
Internal memory (RAM)
Internal memory is volatile
memory;
This is because this memory is
emptied (i.e its contents are
lost) when the computer is
turned off;
00:44:40
Internal memory (RAM)
It is “Random” because any part of
the memory can be accessed
directly by the computer;
RAM is made up of locations, also
known as CELLS;
Each location has a unique address
that never changes.
00:44:40
Internal memory (RAM)
When the computer is switched on,
the operating instructions, computer
programs, and data are moved into
the RAM as required;
RAM empties every time the
computer is switched off – that is
why work has to be saved before
the computer is switched off!!
00:44:40
Random Access memory
(RAM)
RAM is usually measured in
“megabytes”;
The more RAM a computer
has, the more it can do.
00:44:40
Random Access memory
(RAM)
RAM is very fast compared to backup
storage. It is about one thousand
million times faster!
That why a computer needs both a
backup storage and RAM. It uses
RAM for speed and the hard disk to
store data whilst switched off.
00:44:40
Internal memory (ROM)
Read Only Memory (ROM) is not lost
when the computer is switched off;
All computers have a small amount of
ROM;
This is so that essential instructions
can be stored, e.g Instructions to boo
the computer.
00:44:40
Read Only Memory (ROM)
Instructions stored in the ROM enable the
computer to check the hardware and load
the operating systems;
Embedded computer systems usually
have their programs stored i ROM;
ROM are not as fast as RAMs
00:44:40