COAL Chapter 5-6

Central Processing Unit

• Brain of the computer

• Most important component

• Does most of the work

• Performs all types of data processing

 Baran Jons Jakob Berzelius

he discovered silicon in 1823

December 1947

 first transistor was created by John Bardeen, Walter Brattain, William Shockley

1958

first working integrated circuit was built by Robert Noyce and Jack Kilby

1971

Intel 4001 was the company’s first microprocessor (Ted Hoff)

September 2009

Intel released the first Core i5 desktop processor with 4 cores

1. Memory or storage unit

2. Control unit

3. ALU (Arithmetic Logic Unit)

Different Parts of CPU

Memory or Storage Unit

• Can store instructions, data, and intermediate results

• Responsible for transferring information to other units

• Internal storage unit or the main memory

• Primary memory

• Secondary Memory

Types of Memory

• Data and instructions are stored in memory units

• Also stores intermediate results of any calculation

• Finals results of processing are stored

• All sorts of inputs and outputs are transmitted

Main Functions of Memory

• fetch

• decode

• execute

• store

Fundamental Functions of the Computer

• single core CPU

• dual core CPU

• quad core CPU

Types Of CPU

Single Core CPU

oldest type of CPU, only process one operation at a single time

Dual-Core CPU

contains a single integrated circuit with two cores

Quad-Core CPU

contains two dual-core processors

CPU Performance

• How fast a computer’s processor (CPU) can complete the task

• Depends on the processor’s clock speed and others factors

• Versatility

• Performance

• Multi-core

• Compatibility

Advantages of CPU performance

• Overheating

• Power consumption

• Cost

• Limited parallel processing

Disadvantages of CPU Perfomance

Arithmetic Logic Unit (ALU)

• Basic operations of the computers of earlier times are representing and storing numbers

• Mathematical brain

• Digital circuit

• Fundamental building block of the CPU

Intel 74181

first ALU which was implemented as part of the 7400 series TTL

• Data section (data path)

• Control section

CPU can be divided into 2 sections

Bus

• Parallel electrical wires with multiple hardware connections

• Communication system that transfers data between components

• address bus

• data bus

• control bus

Three Types of Bus

Address bus

transfers memory addresses from the processor to components

Data bus

carries the data

Control bus

carries control signals

Registers

• Very fast computer memory

• Serve as gates, sending signals 

• Directed by control unit

• program counter

• instruction register

• memory address register

• memory data register

• general purpose register

Five registers for in-out signal data storage

Program counter

has the address of the next instruction to be executed from memory

Instruction register

holds the instruction currently being executed

Memory address register

 stores the memory address from which data will be fetched

Memory data register

stores the data being transferred to

General purpose register

store temporary data within the microprocessor

Data Path

• Made of functional components, multipliers or ALUs

• Required to do data processing operations

One Bus Organization

A single bus is used for multiple purposes

Two Bus Organization

 to overcome the disadvantage of one bus organization, two buses

In-Bus

the general-purpose register can read data

Out-bus

the general-purpose registers can write data. Here buses get dedicated

Three Bus Organization

 three buses, OUT bus1, OUT bus2, and IN bus

• Increase in size of the registers

• Reduction in the number of cycles for execution

• Increases the speed of execution

Main Advantages of Multiple Bus Organizations