Main Parts of a Personal Computer
Here is a typical PC or Personal Computer system that is possibly similar to the one you are using to study this course.
The Central Processing Unit (Cpu)
The Central Processing Unit (CPU) is a
silicon chip that is the real brain of the computer. It sits inside the system
unit.
Input Devices
To put information into your PC you need an
input device. Two of the most commonly used are shown here, the keyboard and
the mouse.
Output Devices
Computer systems can have many different
output devices. These convert computer data into a form that you can read and
two of the most common are a screen and a printer.
Auxiliary Storage Devices
When you have entered information into your
computer you may need to save it for future use. For this you need either a
floppy disk or one of a variety of internal or external auxiliary storage
devices, some of which we will described later here.
Four Main Components Of A Computer
You have now seen that the components of a
basic personal computer system fall into four categories:
Input Device
System Unit Containing the CPU
Output Device
Auxiliary Storage Unit
Peripheral Devices
All of the pieces of hardware that are
attached to the basic system unit and controlled by the CPU are called
peripheral devices or simply peripherals.
Central Processing Unit (CPU)
What Is The CPU?
The CPU is the silicon chip which functions
as the real 'brain' of the computer. The system case, which contains the
computer's chips and circuits, is often incorrectly referred to as the CPU.
What Does The CPU Do?
The CPU is responsible for the control and
execution of all the computer's operations. It accesses data from memory,
carries out the intended operations and stores the result into memory.
Elements Of The CPU
For this course you only need to understand
the broad concepts of the CPU's control unit, arithmetic and logic unit (ALU)
and internal (register) memory.
Control Unit - The control unit is
responsible for the control and timing of all the tasks being performed by the
CPU. The instruction to be carried out is decoded so that the computer knows
what action to take. A signal to carry out this operation is then sent out to
the ALU.
Arithmetic and Logic Unit - The ALU carries
out the current operation or calculation. The result from the operation is
temporarily stored in a special memory location or register known as the
accumulator.
Internal Memory - The Memory cells inside
the CPU, called registers, are used for the temporary storage of data needed
for the current operation. Values to be operated on and results obtained are
stored in these registers while the operation is being carried out. Once this
is completed the result is moved into the computer's main memory so that the
registers can be cleared for the next operation.
Measuring The Speed Of The CPU
The speed at which the CPU operates is
referred to as the clock speed and is expressed in Megahertz (Mhz).
For example: 60 Mhz = 60 million cycles per
second. 400 Mhz = 400 million cycles per second.
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