CENTRAL PROCESSING UNIT

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CENTRAL PROCESSING UNIT
 The term Central Processing Unit (CPU) was coined in
the early days of computing when a single huge cabinet
housed all the circuitry needed to understand machine-
level program instructions and conduct operations on the
data supplied.
 It also completed all processing for any attached
peripheral devices.
 Early computers only had one CPU and could only
perform one task at a time. Current computers though
have a single CPU, but it can perform multiple task at a
time.
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FEATURES OF CPU
 CPU is considered as the Brain of the computer.
 It performs all types of data processing operations.

 It stores data, intermediate results, and instructions

(program).
 It controls the operation of all parts of the computer.

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CENTRAL PROCESSING UNIT

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BASIC STRUCTURE OF COMPUTER

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COMPONENTS OF CPU: CONTROL UNIT
This unit controls the operations of all parts of the
computer but does not carry out any actual data processing
operations.
Functions of this unit are:
 It is responsible for controlling the transfer of data and
instructions among other units of a computer.
 It manages and coordinates all the units of the computer.

 It obtains the instructions from the memory, interprets

them, and directs the operation of the computer.
 It communicates with Input/Output devices for transfer
of data or results from storage. 6
 It does not process or store data.
COMPONENTS OF CPU: ARITHMETIC
LOGIC UNIT
This unit consists of two subsections namely. These are:
1. Arithmetic Section
Function of arithmetic section is to perform arithmetic
operations like addition, subtraction, multiplication, and
division. All complex operations are done by making repetitive
use of the above operations.
2. Logic Section
Function of logic section is to perform logic operations such as
comparing, selecting, matching, and merging of data.

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COMPONENTS OF CPU: MEMORY UNIT
This unit can store instructions, data, and intermediate
results. This unit supplies information to other units of the
computer when needed.
Its size affects speed, power, and capability. Functions of
the memory unit are:
 It stores all the data and the instructions required for
processing.
 It stores intermediate results of processing.

 It stores the results of processing before these results are

released to an output device.
 All inputs and outputs are transmitted through the main
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memory.
COMPUTER MEMORY
The computer memory holds the data and instructions
needed to process raw data and produce output.
The concept of memory and storage can be easily
conflated as the same concept; however, there are some
distinct and important differences. Memory is primary
memory, while Storage is secondary memory. Memory
refers to the location of short-term data, while storage
refers to the location of data stored on a long-term basis.

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TYPES OF MEMORY
The computer memory is divided into two types. These are:
1. Primary Memory

2. Secondary Memory

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PRIMARY MEMORY (MAIN MEMORY)
Primary memory holds only those data and instructions on
which the computer is currently working. It has a limited
capacity. The data and instruction required to be processed
resides in the main memory. The characteristics are:
 These are semiconductor memories.

 Usually, it is volatile memory in nature.

 Data is lost in case power is switched off.

 It is the working memory of the computer.

 Faster than secondary memories.

 A computer cannot run without the primary memory.

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PRIMARY MEMORY (MAIN MEMORY)
Primary memory is again divided into the following
categories. These are:
1. Random Access Memory (RAM)

RAM (Random Access Memory) is the internal

memory of the CPU for storing data, program, and
program result. It is a read/write memory which stores
data until the machine is working. As soon as the
machine is switched off, data is erased. It has a very
limited amount of space for storage.

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PRIMARY MEMORY (MAIN MEMORY)

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RAM
PRIMARY MEMORY (MAIN MEMORY)
2. Read Only Memory (ROM)
It is the memory from which we can only read but
cannot write on it. This type of memory is non-volatile.
The information is stored here permanently. A ROM
stores such instructions that are required to start a
computer. This operation is referred to as Bootstrap.

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PRIMARY MEMORY (MAIN MEMORY)

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ROM
SECONDARY MEMORY
The secondary storage devices which are built into the
computer or connected to the computer are known as a
secondary memory of the computer. It is also known as
external memory or auxiliary storage.
It is non-volatile, so permanently stores the data even when
the computer is turned off or until this data is overwritten
or deleted. The CPU can't directly access the secondary
memory. First, the secondary memory data is transferred to
primary memory then the CPU can access it.

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SECONDARY MEMORY
The different Secondary memories are:
1. Hard Disk Drive

2. Solid State Drive (SSD)

3. CD (Compact Disk)

4. DVD Drive (Digital Video Display)

5. Pen Drive

6. Blu Ray Disk

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 SECONDARY MEMORY

Hard
Disk CD
Drive

SSD DVD 18
GRAPHICS PROCESSING UNIT (GPU)
A Graphics Processing Unit (GPU) is a chip or electronic
circuit capable of rendering graphics for display on an
electronic device. It is best known for its use in providing
the smooth graphics that consumers expect in modern
videos , gaming and Machine Learning.

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GRAPHICS PROCESSING UNIT (GPU)

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ACCELERATED PROCESSING UNIT
(APU)
 An accelerated processing unit (APU) is a
microprocessor that combines the central processing unit
(CPU) with the graphics processing unit (GPU) on a
single computer chip. It makes a computer a bit faster
than if the processors were set far apart from each other
because, in that case, it would take more time for them to
communicate.
 An Accelerated Processing Unit improves the data
transfer rate between a CPU and a GPU, allowing a
computer to complete tasks while consuming less power
than if the components worked separately.
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THE END

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