Computer Organization

Deals with structural relationships that may not be visible to the

programmer.

Levels of Computer Organization

>Highest Level

> Lowest Level

>Processor-- center for manipulation and control

>Memory – storage for instructions and data for currently executing programs

>I/O system – controller which communicate with “ external” devices: secondary memory, display devices, networks

>Data-path & control – collection of parallel wires, transmits data, instructions, or control signal

A stored program computer has the following basic units:

Brief History of Computing

Wolf Radius Bone

• Wolf radius bone ca. 25,000–30,000 B.C. showing 55 cuts in groups of five, suggesting a rudimentary form of multiplication or division.

Tally Sticks

was an ancient memory aid device to record and document numbers, quantities, or even messages.

Chinese Abacus

• Representation of 39,017 on a Chinese abacus.

Cylinder Music Box

• Victorian Swiss cylinder music box, dated 1862.

Pascal’s Calculating Machine

• Performs basic arithmetic operations (early to mid 1600’s). Does

• not have what may be considered the basic parts of a computer.

Babbage’s Difference Engine #1

• Working portion of Babbage’s Difference Engine No. 1, which is

• the first known automatic calculator.

The Jacquard Pattern Weaving Loom

• The Jacquard pattern weaving loom

Enigma

• Siemens Halkse T-52 Sturgeon (Enigma) cipher machine.

Colossus

• The Colossus (ca. 1944).

The ENIAC

Moore’s Law

• Computing power doubles every 18 months, for the same price.

The von Neumann Model• The von Neumann model consists of five

major components:(1) input unit; (2) output unit; (3) arithmetic logic unit;(4)memory unit; (5) control unit.

BASIC COMPUTER OPERATIONSA computer performs basically five major operations or functions irrespective of their size and make. These are

1) it accepts data or instructions by way of input, 2) it stores data, 3) it can process data as required by the user, 4) it gives results in the form of output, and 5) it controls all operations inside a computer. We

discuss below each of these operations.

1. Input: This is the process of entering data and programs in to the computer system.

2. Storage: The process of saving data and instructions permanently is known as storage

3. Processing: The task of performing operations like arithmetic and logical operations is called processing.

4. Output: This is the process of producing results from the data for getting useful information.

5. Control: The manner how instructions are executed and the above operations are performed.

A Typical Computer System