Basics of Computers: Definition, Computer Generations, Classifications Lecture By Mohamed El.Saied 1

What is a computer ? Monitor Floppy Disk Drive System Unit Keyboard CD-ROM / DVD-ROM Drive Mouse A computer is an electronic device that receives input, process stores and provides output in a useful format(Information) Functions-Accept, Store, Process, Retrieve and Display 2

Generations Of Computers GenerationYearsCharacteristic 1st Use Valves (Vacuum tubes)- ENIAC 2nd Use transistors EDVAC,UNIVAC 3rd Large Scale Integrated Circuits- ALTAIR 4th1975- Very Large Scale Integrated Circuits- APPLE 5thUnder development “Artificial Intelligence” based computers- INTEL- Microprocessor 3

I- Ancient Counting Machines 1- The Abacus (base 5) (in ancient Babylon, China, Europe) Ancient Time 4

II- Mechanical Counting Machines 2- The Pascaline is a mechanical calculating device invented by the French mathematician Blaise Pascal in (+)

II- Mechanical Counting Machines The Leibniz Wheel was invented by the famous mathematician Leibniz in ( +, -, *, / ) 6

II- Mechanical Counting Machines 4- Punched Cards were used by the French weaver Joseph Jacquard in The cards carried weaving instructions for the looms, later this idea offered a great use for storing info

II- Mechanical Counting Machines 5- Charles Babbage’s first computer - Difference Engines to produce tables of numbers This device had mechanical problems similar to those that plagued Pascal and Leibniz. 8

Charles Babbage 2 nd Computer Analytical engine general-purpose used binary system punched cards as input branch on result of previous instruction Ada Lovelace (first programmer) machined parts not accurate enough never quite completed

The Invention of the Vacuum Tube 6- Initially discovered by Thomas Edison, the vacuum tube formed the building block for the entire electronics industry. *Vacuum tubes were later used as electron valves in the 20th century to build the first electronic computers

III- Electrical Counting Machines along with punched cards instead of mechanical gears. In US - Herman Hollerith invented a calculating machine that used electricity

III- Electrical Counting Machines Hollerith’s machine was immensely successful. The general count of the population, then 63 million, took only 6 weeks to calculate! Based on the success of his invention, Herman Hollerith and some friends formed a company that sold his invention all over the world. The company eventually became known as: International Business Machines IBM

III- Electrical Counting Machines 11- MARK I was built by a team from IBM and Harvard University. Mark I used mechanical telephone switches to store information. It accepted data on punched cards, processed it and then output the new data feet long and weighed over 5 tons 13

IV- Electronic Counting Machines 12- The ENIAC was the first US-built all-electronic computer built to perform ballistics calculations. (Away from IBM)

IV- Electronic Counting Machines EDVAC (Electronic Discrete Variable Automatic Computer) UNIVAC (Universal Automatic Calculator)

Two Inventions that changed the way computers are built!! The Transistor The most significant single invention of the modern era. It was invented by 3 scsientists at At&T’s Bell Labs. * Transistors are smaller (sometimes microscopic) * Fast and don’t need to warm up 16

Transistors on a circuit board Transistors Capacitor Resistors 17

Two Inventions that changed the way computers are built!! 1961 The IC revolutionized the entire electronic technology. Ex: The Pentium Processor contains 3.1 Million Transistors in 1.5 inch square! 2- The (IC) Integrated Circuit 18

The AltairThe Apple IThe Floppy Disk The Hard Disk MS-DOS 19

20 What Is a Computer? Computer Take input, process input and provide output Performs computations and makes logical decisions Millions / billions times faster than human beings Computer programs Sets of instructions by which a computer processes data Hardware Physical devices of computer system Software Programs that run on computers  2003 Prentice Hall, Inc. All rights reserved. (modified by Evan Korth)

COMPUTER APPLICATIONS Robotics & Industrial Automation Office Automation Telecommunications Electronic Financial Transactions (Bank) Personal Computers & Teleconferencing Artificial Intelligence (AI) Robotics & Industrial Automation Internet 21

Merits and Demerits of Computer Merits:- 1. Speed- very high speed. Speed is measured in MIPS and BIPS. 1. Accuracy -The results are very correct. 2. Reliability-It gives correct and consistent result always 3. Storage capability-Stores large amounts of data 4. Versatility-Can do different types of jobs 5. Diligence- It won’t get tired De-Merits:- Non-Intelligent-It performs the given instructions only. It does not think on its own. It does not possess any intelligence for analyzing the problem on its own Inactive-If no power supply, it won’t work. 22

Classifications of Computers 1. Supercomputers 2. Mainframe computers 3. Minicomputers (or mid-range computers) 4. Microcomputers Microcomputers 23

Microcomputer Types Desktop Media center system units Notebook or laptop Netbooks Tablet PC Handheld 24

Mini Computers A mini computer faster than a microcomputer. High cost than microcomputers Uses: Industries, Factories 10 SQ Feet area 10 Terminal connected to CPU Eg: Prime

MainFrame Computers A mainframe computer is faster than a mini computer sq. feet area and the most expensive system 100 Terminals+CPU Govenments,Universities Eg:IBM

Super Computers These computers are the fastest, most expensive the extremely powerful Complex mathematical calculations GPS Nuclear Research Eg: Param 27

28 Computer Organization Six logical units of computer system Input unit Mouse, keyboard Output unit Printer, monitor, audio speakers Memory unit Retains input and processed information Arithmetic and logic unit (ALU) Performs calculations Central processing unit (CPU) Supervises operation of other devices Secondary storage unit Hard drives, floppy drives  2003 Prentice Hall, Inc. All rights reserved.

Block Diagram of Computer CPU Storage System Unit ALU CU RAM HD Registers 29

Machine Languages, Assembly Languages, and High-level Languages Three types of programming languages Machine languages Strings of numbers giving machine specific instructions Example: Assembly languages English-like abbreviations representing elementary computer operations (translated via assemblers) Example: LOAD BASEPAY ADD OVERPAY STORE GROSSPAY  2000 Prentice Hall, Inc. All rights reserved. 30

Machine Languages, Assembly Languages, and High-level Languages High-level languages Instructions closer to everyday English English is a natural language. Although high level programming languages are closer to natural languages, it is difficult to get too close due to the ambiguities in natural languages (a statement in English can mean different things to different people – obviously that is unacceptable for computer programming). However, this is a big research area of computer science. Use mathematical notations (translated via compilers) Example: grossPay = basePay + overTimePay Interpreter – Executes high level language programs without compilation.  2003 Prentice Hall, Inc. All rights reserved. 31 (modified by Evan Korth) 31

THANKS 32