CS 1 Notes 1 - Early Computing and 2 - Electronic Computing

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1 CS 1 Notes 1 - Early Computing and 2 - Electronic Computing Computer Science: The discipline that seeks to build a scientific foundation for such topics as: computer design computer programming information processing A is a electromechanical device which can be programmed to change (process) information from one form to another. Do exactly as they are told. Digital devices: Understand only different states ( ) Role of Algorithms Algorithm: A that defines how a task is performed Program: A representation of an Programming: The process of developing a program Software: Programs and algorithms Hardware: Equipment used to input information (data) and output the results of the programs, algorithms. Early examples of algorithms Long division algorithm Euclidean Algorithm The Euclidean algorithm Euclidean algorithm (also called Euclid's algorithm) is an algorithm to determine the greatest common divisor (GCD) of two elements. One of the oldest algorithms known, dating back to the ancient Greeks. Greatest common divisor (GCD): The largest positive integer that divides both numbers without remainder I.e. The largest number that can go into two numbers evenly. Examples: 15 and 6, the GCD is 3 15 / 3 = 5 6 / 3 = 2 48 and 40, the GCD is 8 48 / 8 = 6 40 / 8 = 5 1

2 Early computing devices : positions of beads represent numbers (1600s- 1800s) Positions of gears represent numbers Blaise Pascal, Wilhelm Leibniz, Charles Babbage Babbage s Difference Engine Babbage is credited with inventing the first mechanical computer that eventually led to more complex designs. The first difference engine was composed of around 25,000 parts, weighed fifteen tons (13,600 kg), and stood 8 ft (2.4 m) high. Although he received ample funding for the project, it was never completed. (Wikipedia) Augusta Ada, Countess of Lovelace ( ) Mainly known for having written a description of Charles Babbage's early mechanical general- purpose computer, the analytical engine. She is also known as the "". The computer language Ada, created by the U.S. Defense Department, was named after Ada Lovelace. Early Data Storage Punched cards First used in Jacquard Loom (1801) to store patterns for weaving cloth Storage of programs in Babbage s Analytical Engine Popular through the 1970 s The Jacquard loom was the first machine to use to control a sequence of operations. Did not do computation, but important in history of computer science. The ability to change the pattern of the loom's weave by simply changing cards An important conceptual precursor to the development of computer programming. (Wikipedia) First Generation The brains of early electronic computers were or mechanical switches. The control wire determines whether the circuit is. Mechanical Relays 2

3 When current flows through the coil, an electromagnetic field is created, which attracts the metal arm inside the relay, snapping it shut and... completing the circuit. 3

4 Disadvantage is the arm has mass which makes it. About times per second Not fast enough for solving large computational problems Needed a faster, more reliable alternative to mechanical relays. Second Generation 1904 John Ambrose Fleming invented the thermionic valve (vacuum tube). Later, developed as an electronic switch! Switched of times per second 1930 s Vacuum tubes were used as electronic circuits or. Second Generation Vacuum Tubes The UK ( s) was an electro- mechanical device used by British cryptologists to help decipher German Enigma- machine- encrypted secret messages during World War II. The initial design of the bombe was produced in the UK by. Used thermionic valves (vacuum tubes) for the high speed circuits ENIAC First large- scale electronic digital computer was (Electronic Numerical Integrator and Calculator) First truly general purpose computer 30 feet long, 8 feet wide, and 8 feet high additions every second, (incredibly slow by today s standards). Vacuum tube failures common, one of the first programmers on the Mark- I and the ENAIC. She was the developer of the programming language, says, The Mark- 1 was the first machine that assisted the power of man s brain instead of the strength of his arm. ENIAC was made up of vacuum tubes, over 18,000 of them! Third Generation Needing greater speed and reliability, a better electronic switch was needed Walter Brittain, John Bardeen, and Willaim Shockley invented the transistor at Bell Laboratories Replaced the vacuum tube as an Can switch 10,000 times per second Third Generation - Transistors 4

5 Transistors were: IBM 608 and IBM 608 First fully transistorized computer 3,000 transistors 4,500 additions per second Today s computers use transistors that are 50 nanometers in size Thickness of paper is about 100,000 nanometers thick Super fast switch states millions of times per second and last for decades Developed in Silicon Valley Fourth Generation Integrated Circuits 1959, Jack Kirby and Robert Noyce at Fairchild Semiconductor (who was later to become the cofounder of Intel Corp.) developed the first integrated circuit (silicon chip or microchip). An integrated circuit (IC) is a system of interrelated circuits packaged together on a single sliver of silicon. It is a way of placing multiple (millions) transistor devices into as single, smaller device, the microchip IBM addition every billionth of a second (nanosecond), or a billion additions every second ICs, chips, were: Smaller Faster More reliable Less expensive Fifth Generation - A microprocessor is a Central Processing Unit (CPU) on a single chip. 1971, introduced the first microprocessor chip. Intel khz and contained (equivalent of) 2300 transistors 5

6 IBM used it for calculators not computers Busicom desk- top printing calculator, the world s first commercial product to use a microprocessor. Used the Intel 4004 CPU Altair 8800 Ed Roberts and the first microcomputer or personal computer (for the consumer) the Altair 8800 MITS Altair 8800 Microcomputer - a computer which has a microprocessor. Used the Intel 8080 Microprocessor Microprocessors Personal Computers Computer Basics Embedded Computers Embedded computers Computers found inside consumer goods in order to enhance their function. Cars today might have as many as 50 microprocessors on them. Some of the reasons for this increase in the number of microprocessors are: Meet emissions and fuel- economy standards Advanced diagnostics Reduction of the amount of wiring in cars New safety features New comfort and convenience features Sensors, wearables, medical devices, and more Special Purpose Computers Special purpose or dedicated computers A device with a specific purpose such as game system or information kiosk. Computer is Hardware and Software Hardware versus Software Hardware = The physical components that make up a computer system. More in a moment Much more on all of these items in later presentations! Hardware versus Software Software = The programs (instructions) that tell the computer what to do. System Software Application Software Stored on a storage media such as hard disk, CD- ROM, floppy disk, tape, etc. 6

7 The Processor: The CPU CPU (Central Processing Unit) = A complex collection of electronic circuits on one or more integrated circuits (chips) which: communicates with other parts of the computer system, especially RAM and input devices The CPU is the computer! RAM (Random Access Memory) RAM (Random Access Memory) = integrated circuits (chips) used to store software (programs, instructions) and data primary storage for the CPU electronic switches, storing ON s and OFF s Temporarily stores for the CPU: Software operating system software application software Data data (documents, spreadsheets, etc.) RAM RAM is memory RAM is stores ON and OFF bits (software and data) electrically when power goes off, everything in RAM is lost Why does the CPU use RAM? The CPU is very FAST! The CPU needs the instructions (software) and data as quickly as possible If the CPU has to wait, so does the user Why doesn t the CPU use permanent storage like disk drives? Too slow ROM (Read Only Memory) ROM (Read Only Memory) = integrated circuits (microchips) that are used to permanently store start- up (boot) instructions and other critical information Read Only = information which: Cannot be Cannot be Cannot be appended (added to) Fixed by manufacturer 7

8 ROM is sometimes known as ROM BIOS (Basic Input Output System software) ROM permanently contains: start- up (boot) instructions instructions to do low level processing of input and output devices, such as the communications with the keyboard and the monitor = software program which is stored permanently on a microchip, such as the software on the ROM chip Application Software Performs specific tasks: Word processing Calculations Information storage and retrieval Accounting Cannot function without the OS (Operating System) Written for a specific operating system and computer hardware. Operating System Software Loads automatically when you switch on a computer Main roles: Controls Permits you to Acts as intermediary between user and applications Software which manages the overall operation of the computer system including: hardware (CPU, RAM, I/O) security system interface application interface 8

Evolution of the Computer

Evolution of the Computer Janaka Harambearachchi (Engineer/Systems Development) Zeroth Generation- Mechanical 1. Blaise Pascal -1642 Mechanical calculator only perform + - 2. Von Leibiniz -1672 Mechanical