computer overview

Computer overview

I s an automatic, electronic machine that Computer

o   accept data & instructions from a user (INPUT)

o   store the data & instructions (STORAGE)

o   manipulate the data according to the instructions (PROCESSING)

o   store &/or output the results to the user (OUTPUT)

TYPE OF COMPUTER

•      Computers range in size and capability.

•      At one end of the scale are supercomputers, very large computers with thousands of linked microprocessors that perform extremely complex calculations.

•      At the other end are tiny computers embedded in cars, calculators, and appliances. These computers are built to perform a limited number of tasks.

•      The personal computer, or PC, is designed to be used by one person at a time. This section describes the various kinds of personal computers: desktops, laptops, handheld computers, and Tablet PCs.

Desktop computers

•      Desktop computers are designed for use at a desk or table.

•      They are typically larger and more powerful than other types of personal computers.

•      Desktop computers are made up of separate components.

•      The main component, called the system unit

•      Other components are monitor, mouse, and keyboard, connect to the system unit

.

LAPTOP COMPUTER

•       Laptop computers are lightweight mobile PCs with a thin screen.

•      They are often called notebook computers because of their small size.

•      Laptops can operate on batteries, so you can take them anywhere.

•      Unlike desktops, laptops combine the CPU, screen, and keyboard in a single case.

•      The screen folds down onto the keyboard when not in use.

LAPTOP

Handheld computers

•      Handheld computers, also called personal digital assistants (PDAs), are battery-powered computers small enough to carry almost anywhere.

•      Not powerful as desktops or laptops

•      These are useful for scheduling appointments, storing addresses and phone numbers, and playing games.

•      Some have more advanced capabilities, such as making telephone calls or accessing the Internet.

•      Handhelds have touch screens that you use with your finger or a stylus (a pen-shaped pointing tool).

Handheld computer

Tablet PCs

•      Tablet PCs are mobile PCs that combine features of laptops and handhelds.

•      Like laptops, they're powerful and have a built-in screen.

•      Like handhelds, they allow you to write notes or draw pictures on the screen, usually with a tablet pen.

•      They can also convert your handwriting into typed text.

•      Tablet PC

 

Basic Parts of Computer

•      Hardware

–     Mechanical devices in the computer

–     Anything that can be touched

•      Software

–     Tell the computer what to do

–     Also called a program

–     Thousands of programs exist

Hardware

•      Hardware is basically anything that you can touch with your fingers.

§  Computer Case

§   CPU (central processing unit...Pentium chip)

§   Monitor

§   Keyboard & Mouse

§   CD-ROM, DVD,

§   Hard   Drive

§   Memory (RAM)

§   Speakers

§   Printer

Hardware

•      There are 4 basic types of hardware

§  Input Devices

§  Output Devices

§  Storage Devices

§  Processing Devices

Input Devices

•      Input basically means getting data into the computer to be processed.

•      The most common input devices are Keyboard and Mouse,

Output Devices

•      Output basically means getting data out of the computer.

•      Examples are

§  Monitor

§  Printer

§  Speakers

Storage Devices

•      Storage devices are the one used to keep data that has been processed so that data can be retrieved at a later time to be used again.

•      Examples are:                                             hard disc

§  Hard Disk                                       

 Floppy disc

§  Floppy Disk

§  CD’s, DVD’s

Processing Device

•      Central Processing Unit (CPU)

§  The main chip in the computer.

§  It is the heart of the computer and communicates with the output, input and storage devices to perform tasks that are important to the functioning of the computer.

CPU

•      Its main function is

§  to process instructions

§  manage the flow of information through the computer system.

§  perform calculations.

•      CPU composed of two main components:

•      Control Unit

•      Arithmetic and Logic Unit (ALU)

Control Unit

•      Tells the rest of the Computer system how to carry out a program’s instructions.

•      It direct the movement of electronic signals between memory and ALU

•      It also direct these control signals between the CPU and output device

Arithmetic and Logic Unit

   This performs two types of operation, arithmetic and logical

§  Arithmetic Operations: Are fundamental math operations; addition, subtraction, multiplication and division.

§  Logical Operations: Consists of comparisons. That two pieces of data or more are compared to see whether one is equal to (=), less than (<), or greater than (>) the other, etc

ABACUS 4^th Century B.C.

The abacus, a simple counting aid, may have been invented in Babylonia (now Iraq) in the fourth century B.C.

This device allows users to make computations using a system of sliding beads arranged on a rack.

BLAISE PASCAL

(1623 - 1662)

In 1642, the French mathematician and philosopher Blaise Pascal invented a calculating device that would come to be called the "Adding Machine".

Originally called a "numerical wheel calculator" or the "Pascaline", Pascal's invention utilized a train of 8 moveable dials or cogs to add sums of up to 8 figures long. As one dial turned 10 notches - or a complete revolution - it mechanically turned the next dial.

Pascal's mechanical Adding Machine automated the process of calculation. Although slow by modern standards, this machine did provide a fair degree of accuracy and speed.

CHARLES BABBAGE

(1791 - 1871)

Charles Babbage was an English mathematician and professor.

 In 1822, he persuaded the British government to finance his design to build a machine (called difference engine and later analytical engine) that would calculate tables for logarithms.

With Charles Babbage's creation of the "Analytical Engine", (1833) computers took the form of a general purpose machine.

Charles Babbage is called father of computer

Aiken thought he could create a modern and functioning model of Babbage's Analytical Engine.

He succeeded in securing a grant of 1 million dollars for his proposed Automatic Sequence Calculator; the Mark I for short. From IBM.

In 1944, the Mark I was "switched" on. Aiken's colossal machine spanned 51 feet in length and 8 feet in height. 500 meters of wiring were required to connect each component.

HOWARD AIKEN (1900 - 1973)

The Mark I did transform Babbage's dream into reality and did succeed in putting IBM's name on the forefront of the burgeoning computer industry. From 1944 on, modern computers would forever be associated with digital intelligence

ENIAC  1946

Electronic Numerical Integrator And Computer

Under the leadership of J. Presper Eckert (1919 - 1995) and John W. Mauchly (1907 - 1980) the team produced a machine that computed at speeds 1,000 times faster than the Mark I was capable of only 2 years earlier.

Using 18,00-19,000 vacuum tubes, 70,000 resistors and 5 million soldered joints. This massive instrument required the output of a small power station to operate it.

ENIAC 1946

It could do nuclear physics calculations (in two hours) which it would have taken 100 engineers a year to do by hand.

The system's program could be changed by rewiring a panel.

TRANSISTOR1948

In the laboratories of Bell Telephone, John Bardeen, Walter Brattain and William Shockley discovered the "transfer resistor"; later labelled the transistor.

Advantages:

increased reliability

1/13 size of vacuum tubes

consumed 1/20 of the electricity of vacuum tubes

were a fraction of the cost

TRANSISTOR 1948

This tiny device had a huge impact on and extensive implications for modern computers. In 1956, the transistor won its creators the Noble Peace Prize for their invention.

ALTAIR 1975

The invention of the transistor made computers smaller, cheaper and more reliable. Therefore, the stage was set for the entrance of the computer into the domestic realm. In 1975, the age of personal computers commenced.

Under the leadership of Ed Roberts the Micro Instrumentation and Telemetry Company (MITS) wanted to design a computer 'kit' for the home hobbyist.

Based on the Intel 8080 processor, capable of controlling 64 kilobyes of memory, the MITS Altair - as the invention was later called - was debuted on the cover of the January edition of Popular Electronics magazine.

Presenting the Altair as an unassembled kit kept costs to a minimum. Therefore, the company was able to offer this model for only $395. Supply could not keep up with demand.

ALTAIR FACTS:

No Keyboard

No Video Display

No Storage Device

IBM (PC) 1981

On August 12, 1981 IBM announced its own personal computer.

Using the 16 bit Intel 8088 microprocessor, allowed for increased speed and huge amounts of memory.

Unlike the Altair that was sold as unassembled computer kits, IBM sold its "ready-made" machine through retailers and by qualified salespeople.

To satisfy consumer appetites and to increase usability, IBM gave prototype IBM PCs to a number of major software companies.

For the first time, small companies and individuals who never would have imagined owning a "personal" computer were now opened to the computer world.

MACINTOSH (1984)

IBM's major competitor was a company lead by Steve Wozniak and Steve Jobs; the Apple Computer Inc.

The "Lisa" was the result of their competitive thrust.

This system differed from its predecessors in its use of a "mouse" - then a quite foreign computer instrument - in lieu of manually typing commands.

However, the outrageous price of the Lisa kept it out of reach for many computer buyers.

Apple's brainchild was the Macintosh. Like the Lisa, the Macintosh too would make use of a graphical user interface.

Introduced in January 1984 it was an immediate success.

The GUI (Graphical User Interface) made the system easy to use.

The Apple Macintosh debuts in 1984. It features a simple, graphical interface, uses the 8-MHz, 32-bit Motorola 68000 CPU, and has a built-in 9-inch B/W screen.

Computer Generations

FIRST GENERATION

(1945-1956)

First generation computers were characterized by the fact that operating instructions were made-to-order for the specific task for which the computer was to be used.

Each computer had a different binary-coded program called a machine language that told it how to operate.

This made the computer difficult to program and limited its versatility and speed.

Other distinctive features of first generation computers were the use of vacuum tubes for circuitry (responsible for their breathtaking size) and magnetic drums for data storage.

Problems:

Vacuum tube generated a great deal of heat

Tubes burnt out frequently

Thus, first generation computers were Huge, Slow, Expensive, Unreliable

The  ENIAC and UNIVAC are first generation computing devices

CHARACTERISTICS

First generation computers were based on vacuum tubes.

The operating systems of the first generation computers were very slow.

They were very large in size.

Production of the heat was in large amount in first generation computers

 Machine language was used for programming.

First generation computers were unreliable.

They were difficult to program and use.

UNIVAC, EDVAC, EDSAC and ENIAC computers are examples of first generation computing devices.

SECOND GENERATION

(1956-1963)

These second generation computers were also of solid state design, and contained transistors in place of vacuum tubes

Transistors

Were smaller than vacuum tubes

They needed no warm up time

Consumes less energy

Generate much less heat

Faster and more reliable

These computers were smaller, faster and cheaper

They also contained all the components we associate with the modern day computer: printers, tape storage, disk storage, memory, operating systems, and stored programs.

One important example was the IBM 1401

CHARACTERISTICS

Transistors were used in place of vacuum tubes.

Second generation computers were smaller in comparison with the first generation computers.

They were faster in comparison with the first generation computers.

They generated less heat and were less prone to failure.

They took comparatively less computational time

Assembly language was used for programming.

Second generation computers has faster input/output devices.

IBM 7000, NCR 304, IBM 650, IBM 1401, ATLAS and Mark III are the examples of second generation computers.

THIRD GENERATION

(1956-1963)

Though transistors were clearly an improvement over the
 vacuum tube, they still generated a great deal of heat, which damaged the computer's sensitive internal parts.

The development of integrated circuit (IC) signal the beginning of the third generation computers

Integrated circuit (IC) is a collection of  transistors and electrical circuits all in a single crystal called microchip

The microchip is a complete electronic circuit on a small chip silicon knows as a semi-conductor

Integrated circuit technology reduced the size and cost of computers

Today’s integrated circuits are no more than a centimeter long, and they can carry millions of microscopic transistors

As a result, computers became ever smaller as more components were squeezed onto the chip.

Another third-generation development included the use of an operating system that allowed machines to run many different programs at once with a central program that monitored and coordinated the computer's memory.

Advantages of integrated circuits:

Silicon chips were reliable, compact  and cheaper

Sold hardware and software separately which created the software industry

Customer service industry grew

 General characteristics of this computer generation

IC was used instead of transistors in the third generation computers.

Third generation computers were smaller in size and cheaper as compare to the second generation computers.

 They were fast and more reliable.

High level language was developed.

Magnetic core and solid states as main storage.

 They were able to reduce computational time and had low maintenance cost.

Input/Output devices became more sophisticated.

PDP-8, PDP-11, ICL 2900, IBM 360 and IBM 370 are the examples of third generation computers.

FOURTH GENERATION (1971-Present)

The microprocessor brought the fourth generation of computers as thousands of integrated circuits were built onto a single silicon chip

The microprocessor is a large scale integrated circuit on a tiny silicon chip that contains thousands or millions of transistors in in multiple ICs.

A microprocessor containing about 100 components is called LSI (Large Scale Integration) and the one, which has more than 1000 such components, is called as VLSI (Very Large Scale Integration). 

CHARACTERISTICS

The fourth generation computers have microprocessor-based systems

They are the cheapest among all the computer generation.

The speed, accuracy and reliability of the computers were improved in fourth generation computers.

Many high-level languages were developed in the fourth generation such as COBOL, FORTRAN, BASIC, PASCAL and C language.

A further refinement of input/output devices was developed.

Networking between the systems was developed

IBM 4341, DEC 10, STAR 1000, PUP 11 and APPLE II are the examples of fourth generation computers

FIFTH GENERATION  (present & beyond)

Fifth generation computing devices are based on artificial intelligence and they are still in development

Computers today have some attributes of fifth generation computers and applications such as voice recognition are being used today

The use of parallel processing and superconductors is helping to make artificial intelligence a reality.

Quantum computation and molecular and nanotechnology will radically change the face of computers in years to come.

The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization.

5th generation computers use ULSI (Ultra-Large Scale Integration) chips. Millions of transistors are placed in a single IC in ULSI chips

CHARACTERISTICS

 The fifth generation computers will use super large scale integrated chips

 They will have artificial intelligence.

They will be able to recognize image and graphs.

Fifth generation computer aims to be able to solve highly complex problem including decision making, logical reasoning.

They will be able to use more than one CPU for faster processing speed.

Fifth generation computers are intended to work with natural language.