Computer Architecture and Organization

                                        Chapter 1

                            History of Computers

Topics that we discussed:

• History of Computer

• Types of Computer

• Computer Architecture and Organization

                 

Definition of Computer 

• Computer is a programmable machine.

• Computer is a machine that manipulates data according to a list of instructions.

• Computer is any device which aids humans in

performing various kinds of computations or

calculations. 

 

Three principles characteristic of computer:

•It responds to a specific set of instructions in a well defined manner.

•It can execute a pre-recorded list of instructions.

•It can quickly store and retrieve large amounts of

data. 

                     Earliest Computer

•Originally calculations were computed by humans,

whose job title was computers.

•These human computers were typically engaged in the

calculation of a mathematical expression.

•The calculations of this period were specialized and

expensive, requiring years of training in mathematics.

•The first use of the word "computer" was recorded in

1613, referring to a person who carried out

calculations, or computations, and the word continued

to beA in that sense until the middle of the 20th

century

 

                      Tally Sticks

≈A tally stick was an ancient memory aid device to

record and document numbers, quantities, or even

messages. 

Abacus 

• An abacus is a mechanical device used to aid an

individual in performing mathematical calculations.

• The abacus was invented in Babylonia in 2400 B.C.

• The abacus in the form we are most familiar with

was first used in China in around 500 B.C.

•It used to perform basic arithmetic operations.

Napier’s Bones

•Invented by John Napier in1614.

•Allowed the operator to multiply, divide and calculate square and cube roots by moving the rods around and placing them in specially constructed boards. 

Slide Rule

•Invented by William Oughtred in 1622.

•Is based on Napier's ideas about logarithms.

•Used primarily for

– multiplication

–division

– roots

– logarithms

– Trigonometry

• Not normally used for addition

or subtraction. 

Pascaline

•Invented by Blaise Pascal in 1642.

•It was its limitation to addition and subtraction.

•It is too expensive. 

Stepped Reckoner

•Invented by Gottfried Wilhelm Leibniz in 1672.

• The machine that can add,subtract, multiply and divide automatically. 

Jacquard Loom

• The Jacquard loom is a mechanical loom,invented by Joseph-Marie Jacquard in 1881.

•It an automatic loom controlled by punched cards.

Arithmometer

• A mechanical calculator invented by Thomas de Colmar in 1820,

• The first reliable, useful and commercially successful

calculating machine.

• The machine could perform the four basic mathematic functions.

• The first mass-produced calculating machine.

 

Difference Engine and Analytical Engine

•It an automatic, mechanical calculator designed to tabulate polynomial functions.

•Invented by Charles Babbage in 1822 and 1834

•It is the first mechanical computer.

First Computer Programmer

•

In 1840, Augusta Ada Byron

suggests to Babbage that he use

the binary system.

• She writes programs for the Analytical Engine.

Scheutzian Calculation Engine

• Invented by Per Georg Scheutz in 1843.

• Based on Charles Babbage's difference engine.

• The first printing calculator. 

Tabulating Machine

•Invented by Herman Hollerith in 1890.

• To assist in summarizing information and accounting.

Havard Mark 1

• Also known as IBM Automatic Sequence Controlled Calculator (ASCC).

•Invented by Howard H. Aiken in 1943

• The first electro-mechanical computer.

Z1

• The first programmable computer.

• Created by Konrad Zuse in

Germany from 1936 to 1938.

• To program the Z1 required that

the user insert punch tape into a

punch tape reader and all output

was also generated through

punch tape.

    

ENIAC

 

ENIAC stands for Electronic Numerical Integrator and

Computer.

•It was the first electronic generalpurpose computer.

• Completed in 1946.

•Developed by John Presper Eckert and John W. Mauchl.

 

UNIVAC

•The UNIVAC I (UNIVersal Automatic Computer 1)

was the first commercial computer.

•Designed by J. Presper Eckert and John Mauchly.

Computer architecture and Computer Organization

Computer Architecture

• refers to those attributes of a system visible to a programmer. In other words, we can also say that the computer architecture refers to the attributes that have a direct impact on the logical execution of the program.

 Computer organization

•refers to the operational units and their interconnections that realize the architectural specifications.

•Realization of what COMPUTER

Scified by the computer architecture . It deals with how operational attributes are linked together to meet the requirements specified by computer architecture. Some organizational attributes are hardware details, control signals, peripherals.

BASIC FUNCTIONAL UNITS OF COMPUTER

The basic organization of a computer system is the processing unit, memory unit, and input-output devices. The processing unit controls all the functions of the computer system. It is the brain of the computer e.g. CPU. The memory unit consists of two

                      Operational Unit

OUTPUT UNIT.                        INPUT UNIT

       •>Monitors.                         •Keyboard

       •>Speakers.                         •Joystick

       •>Projector.                         • Track Ball.

      •Headphone                         • Digitizer.     

 

Input Unit

= A computer accepts a digitally coded information through input unit using input

devices. The most commonly used input devices are keyboard and mouse. The

keyboard is used for entering text and numeric information. 

Memory Unit

• The memory unit is used to store programs and data. Usually, two types of memory

devices are used to from a memory unit : primary storage memory memory device

and secondary storage memory device. 

Arithmetic and logic unit (ALU)

• is responsible for performing arithmetic

operations such as add, subtract, division and multiplication, and logical operations

such as ANDing, ORing, Inverting etc. 

TYPES OF COMPUTER ARCHITECTURE 

Von Neumann Architecture

The Von Neumann architecture, also known as the Princeton architecture, is a computer architecture based on that described in 1945 by the mathematician and physicist John Von Neumann.

non von Neumann architecture 

Any computer architecture in which the underlying model of computation is different from what has come to be called the standard von Neumann model (see von Neumann machine).

Classification of Non Von Neumann Architecture

•Harvard Architecture

•Modified Harvard architecture

Reflection ;The subject explores how machines are designed, built, and operate. Knowing what's inside and how it works will help you design, develop, and implement applications better, faster, cheaper, more efficient, and easier to use because you will be able to make informed decisions instead of guestimating and assuming.