History Of Computers 1

THE HISTORY OF COMPUTERS

EARLY HISTORY (before 1800’s)

ABACUS

LEIBNITS adding machine early 1700’s

SLIDE RULE 1600’s

BLAISE PASCAL adding machine 1642

Jacquard loom

The first was developed by a French textile manufacturer called Joseph Jacquard. He invented a punch card system for programming the designs on a carpet making loom. First he used single cards to control the pattern of the threads. On later machines the cards were joined together to form repeating patterns. This idea of punch cards was adopted for use with musical instruments, such as the barrel organ. Here a sequence of valves were opened and closed controlling air flow into various organ pipes. Tunes could be programmed and loaded into the machine.

BABBAGE difference engine

In the 1820’s Charles Babbage designed a mechanical machine called the Difference engine. The purpose of this machine was to calculate and print out tables for the Admiralty. (i.e., tides, tables and planetary positions for navigation). The machine consisted of cog wheels that could be set in keyed positions, these turned as the computations were performed. Due to the limitations of mechanical engineering in this period, and lack of money, the machine was never completed.

BABBAGE’S analytical engine A mechanical computer that can solve any mathematical problem. It used punch-cards similar to those used by the Jacquard loom and can perform simple conditional operations. According to Babbage ,an automatic Computing machine must have:A store for the numbers. - Referred to as memory. A device for performing arithmetic operations, he called this a mill. -Referred to as the arithmetic unit or central processor unit (CPU). A device for causing the operations of the machine, for example transferring numbers from one place to another. -Referred to as the control unit. An input and output device. Such as card reader or printer. - Includes screen, mouse & Keyboard.

COMPUTER MATHEMATICS AND PHILOSOPHY George Boole (1815 to 1864)

Bertrand Russell (1872 to 1970)

Kurt Godel (1906 to 1978)

1718 medallion Showing binary numbers

HARVARD MARK I and II The modern computer era commenced with the first large-scale automatic digital computer, which was developed between 1939 and 1944. The Harvard Mark I and II was the invention of Howard Aiken. The machines were constructed out of switches, relays and rotating shafts.

In 1945, LTJG Grace Murray was working on the Harvard University Mark II Aiken Relay Calculator. While testing Mark II due to a malfunction, a moth was found trapped between the points of a Relay. The operators removed and affixed the moth to the computer log, with the entry: "First actual case of bug being found." They put out the word that they had "debugged" the machine, thus introducing the term "debugging a computer program."

DECODING MACHINES COLOSSUS

Bletchley park’s bombe

The worlds first electronic computer (ie, using valves) called Colossus was built in 1943. It became operational on February 1944 at Dollis Hill in North London and was designed help decode German messages during the war. It read data at 5000 characters per second, had a clock speed of 5KHz and used 4. 5 KWatts of power. The computers program had to be “patched” in (ie, hardware rewired) every time a new program was needed, this could take many hours.

THE MANCHESTER COMPUTER (first generation) The world's first storedprogram electronic digital computer successfully executed its first program on 21st June 1948. It was designed and constructed at Manchester University. Later that year Ferranti Ltd. Was given the rights to manufacture and sell a commercial version of the machine (Manchester mark I) Electronic valve

1946: Williams Tube CRT Memory Storage Unit

FERRITE CORE MEMORY

Current passing through The core flips the magnetic field direction, this is detected by a “sense wire”

THE TRANSISTOR

Transistor Logic Gate

First Transistor Uses Silicon developed in 1948 Second Generation Computers used Transistors

Computing in the 1960’s (second generation) Large main frame computers discrete transistor circuit boards

modem

Teletype

Computer room

INTEGRATED CIRCUITS (third generation)

Mini computers made from logic gates on IC chips Small scale integrated circuits (RTL, DTL, TTL, CMOS)

Integrated Circuits

MICROPROCESSOR (fourth generation)

Name 8080 8088 80286 80386 80486 Pentium Pentium II Pentium III

date 1974 1979 1982 1985 1989 1993 1997 1999

Transistors 6000 29000 134000 275000 1200000 3100000 7500000 9500000

Microns Clock speed 6 3 1.5 1.5 1.0 0.8 0.35 0.25

2MHz 5MHz 6MHz 16MHZ 25MHz 60MHz 233MHz 450MHz

Data bits 8 bit 16 bit 16 bit 32 bit 32 bit 32 bit 32 bit 32 bit

MIPS 0.64 (first home computers) 0.33 (first IBM PC) 1 (12 MHz AT version) 5 (eventually 33MHz) 20 (eventually 50MHz) 100 (eventually 200MHz) 400 (eventually 450MHz) 1000 ?

The First Microprocessor – 1971 The 4004 had 2,250 transistors four-bit chunks (four 1’s or 0’s) 108Khz,Called “Microchip”

Computer architectures (fifth generation) Computer Architecture is the science and art of selecting and interconnecting hardware components to create computers that meet functional, performance and cost goals

Harvard:Separate data paths exist for the transfer of instructions and data Von Neumann:Uses the same storage device for both instructions and data

COMPUTER CONCEPTS Vocabulary

Central processing unit (CPU) The main processing unit in a computer, consisting of circuitry that executes instructions to process data.

Computer A device that accepts input, processes data, stores data, and produces output.

Data In the context of computing and data management, data refers to the symbols that a computer uses to represent facts and ideas.

Input As a noun, "input" means the information that is conveyed to a computer. As a verb, "input" means to enter data into a computer.

Memory The computer circuitry that holds data waiting to be processed.

Output The results produced by a computer (for example, reports, graphs, and music).

Process A systematic series of actions that a computer performs to manipulate data; typically represented on a DFD(Data Flow diagram) by a rounded rectangle.

Storage The area in a computer where data is retained on a permanent basis.

Hardware Electronic and mechanical devices used for input, output, processing, and storing data.

Peripheral devices Components and equipment that expand a computer's input, output, and storage Capabilities. Examples: Printer or scanner.

Software The instructions that set up a computer to do a task, indicate how to interact with a user, and specify how to process data.

Desktop microcomputer A computer that is built around a single microprocessor chip and is small enough to fit on a desk.

Microcomputer A category of computer that is built around a single microprocessor chip. The computers typically used in homes and small businesses (also called a personal computer).

Notebook computer A small lightweight portable computer that usually runs on battery power. Sometimes called a laptop.

Personal digital assistant (PDA) A computer that is smaller and more portable than a notebook computer (also called a palm-top computer).

Minicomputer A midrange computer, somewhat larger than a microcomputer, that can carry out processing tasks for many simultaneous users.

Terminal A device with a keyboard and a monitor, used for input and output, but not for processing.

Mainframe A large, fast, and expensive computer generally used by businesses or the government to provide centralized storage processing and management for large amounts of data.

Supercomputer The fastest and most expensive type of computer, capable of processing more than one trillion instructions per second.

CD-ROM disk A high capacity read-only optical disk that can store up to 700 MB of data. An acronym for compact disc read-only memory.

CD-ROM drive A storage device that uses laser technology to read data from a CDROM.

Disk drive A computer storage device that records and retrieves data on disks. Drive types include floppy, Zip, hard disk drives.

DVD An optical storage medium similar in appearance and technology to a CDROM but with higher storage capacity. The acronym stands for "digital video disc" or "digital versatile disc."

Floppy disk A removable magnetic storage medium, typically 3.5" in size with a capacity of 1.44 MB.

Mouse An input device that allows the user to manipulate objects on the screen by moving the mouse on the surface of a desk.

Computer platform A hardware and software configuration shared by a group of computers that use the same software and peripheral devices.

PC A microcomputer that uses the Windows software and contains an Intelcompatible micro-processor. A personal computer.

Computer network A collection of computers and related devices, connected in a way that allows them to share data, hardware, and software.

Password A special set of symbols used to restrict access to a user's computer or network.

Internet The worldwide communication infrastructure that links computer networks using TCP/IP protocol.

Web Short for World Wide Web. An Internet service that links documents and information from computers distributed all over the world. Uses HTTP protocol.

User interface The software and hardware that enable people to interact with computers.

Command-line interface A type of user interface that requires the user to type in commands.

Syntax Specifications or rules for the sequence and punctuation of command words and parameters.

Syntax error An error that results when an instruction does not follow the syntax rules, or grammar, of the programming language.

Icon A graphical representation of an object such as a disk, printer, or program.

Window A rectangular representation of a work area in a graphical user interface.

Graphical user interface (GUI) A type of user interface that features onscreen objects such as menus and icons, manipulated by a mouse. Abbreviated GUI (pronounced "gooey").

Pixel Short for picture element, a pixel is the smallest unit in a graphic image. Computer display devices use a matrix of pixels to display text and graphics.

Resolution The density of the grid used to display or print text and graphics. The greater the horizontal and vertical density, the higher the resolution.

Web browser software Computer software, such as Netscape Navigator and Microsoft Internet Explorer, that allows users to view Web pages and follow links to jump from one document to the next.

Web search engine A feature of a Web site that allows users to search for information by entering key terms.

Artificial intelligence (Al) A characteristic of computers that exhibit human-like intelligence or behaviors. A field of research that includes robotics, expert systems, and speech recognition.

Computer program A set of detailed, step-by-step instructions that tells a computer how to solve a problem or carry out a task.