COMPUTER SYSTEM
THE CPU AND STORAGE
SYSTEM UNIT
•
• Is a central part of a computer system.
It is usually a box which you can physically see.
The system box consists of electronic components that process
information.
They are Central Processing Unit and Memory (RAM and ROM)
The most important of these is the Central Processing Unit (CPU)
THE CENTRAL PROCESSING UNIT (CPU) or MICROPROCESSOR acts as a brain of the computer.
It receives data from the input devices and process it into information.
When processing input the CPU uses the main memory to hold data, instructions and
information temporarily.
The CPU has two parts:
ALU and Control Unit
Arithmetic Logic Unit (ALU) which performs arithmetic operations (addition, subtraction,
multiplication and division) and Logical operations.
The logical operations ae comparisons, therefore is equal to (=), greater than (>), less than (<),
less than or equal to (<=), greater than or equal to (>=) or not equal (?) to the other, are used.
CONTROL UNIT
Control Unit interprets each instruction stored in the CPU and then carries out the
instructions. It directs electronic signals between main memory and ALU, and also between
the main memory and the peripheral devices.
MEMORY
Memory refers to both Random Access Memory (RAM) and Read Only Memory
(ROM), although in some cases only refers to RAM. Both the RAM and Rom
are normally referred to as INTERNAL MEMORY.
Internal memory is contained on small microchips that are on the computer’s
motherboard.
PROCESSORS
CPU is also called a processor.
There are different types of processors on the market with different speeds. The speed is
measured in Megahertz (MHz) or gigahertz (GHz).
MHz measure the frequency equivalent to one million cycles (ticks of the system clock)
while GHz equates to a billion cycles per second. A processor has a system clock that
controls how fast all the operations within a computer take place.
PCs run on processors manufactured by Intel Corporation or Advanced Micro Devices(AMD).
Intel markets its processor under the name Pentium, Celeron, Xeon or Itanium.
Refer to page 35 Learners textbook.