CONCISE COMPUTER SCIENCE HISTORY OF COMPUTERS Performance objectives TEXTBOOK FOR CHILDREN Pupils should be able to: BOOK III i. Identify early counting devices ii. Identify early mechanical calculating devices iii. Identify the landmarks in the transition of early calculating devices to present day computers.

EARLY COUNTING DEVICES , COUNTING WITH FINGERS, TOES, PEBBLES, STONES AND STICKS. In the olden days, before the introduction or invention of computers. Our forefathers were once using pebbles, stones, sticks and fingers to count their products and commodities. Also in the olden days, human being communicates only through words, both written and spoken. In the ancient times until about 150 years ago, messages and information were either verbal or written system. Getting a message to a distant recipient was often slow and sometimes the message (or the messenger) got lost in the . As science and technology proceeded, scientists BY: developed devices as to help them calculate and communicate faster over greater distances. Traditional devices like Abacus and Calculator are traditional WOLE ADEDOYIN calculating devices used for solving simple calculations in the olden days. GENERATION OF COMPUTER (iii) Third generation computers (1965-1970) The growth of computer can be divided into five distinct generations. Each refers to the distinct technological break These are computer produced using the technology of the through in the development of computers. middle 1960’s. They were designed using Integrated Circuits (ICTs). With these ICs, hundreds of electrical components (i) First generation computer (1940-1958) were built into silicon Chip. The Magnetic Core and the Solid- This generation was characterized by the use of vacuum state remained the primary memory. They were faster, more tubes or thermionic valves. These tubes, though the best reliable, less expensive. and lighter in weight. IBM introduction material the technology could offer at this time, made the the IBM system/360 in 1964 and has ever remained in the computers unnecessarily big, dissipated a lot of heat, costly, fore-front. very slow and unreliable when compared with computers of The use of integrated Circuits was later followed by Medium later generations. They made use of Magnetic Drum as the Scale of Integration (MSI and large Scale of Integration of the primary storage medium. Examples are EDSAC, EDVAC, and electrical components. These led to a further reduction in size, UNIVAC 1 & II reliability and overall manufacturing costs. These gave birth to the microcomputers and minicomputers and the revolutionary (ii) Second generation computers (1959-1964) effect on the industry from the early 70s cannot be over- The computers of this generation were designed with emphasized. electronic transistors. They proved more reliable, cost less, faster and smaller in size. Similarly, the Magnetic Core (iv) Fourth generation computers (1971-1985) replaced the Magnetic Drum as the primary storage medium. Examples are Boroughs 200series. Honey-well 800, IBM This generation is characterized by the use of very large scale 7070, 7080, IBM 1600 series, UNIVAC III etc. integrated circuits (VLSICs) which mans many components in very small space, and the use of bubble memories. This was a thin line of demarcation between the third and the fourth generations. This further led to reduction in the physical fifth generation. This generation was characterized by the components of the computer. advent of Artificial Intelligence (AI), Speech Processing, Through VSLIC, it was possible to build over 20, 00 Parallel Architecture, Pattern Recognition, Expert System, and components onto a small piece or a single silicon chip (about Multimedia System. the size of a finger tip). This technique led to the invention of

Microprocessors and hence the both of the pocket calculators and digital watches.

Artificial Intelligence is the ability of the computer exhibit behaviors like an intelligent person. An Expert System, on the other hand, is an application program that has the capability

of making judgments and decision like an expert in a particular field of application. It is an interactive system that pits users through question and answer sessions to clarify

issues and make recommendations. An example is in the field

of medicine, where a computer would prescribe like a doctor after performing the needed diagnoses. By the middle of (v) Fifth generation computer (1985-Date) 1998, the American celebrated the debut of the Voice Recognition System . Many schools of thought classified the advent of the

Japanese industrial robots as a distinct generation. Hence the

PHOTOGALLERY OF 2ND AN

3RD GENERATION OF COMPUTER

Differential Analyzer

Lord Kelvin’s Tide Predictor Harmonic Analyzer

EARLY COUNTING DEVICES

Hollerith tabulating machine

Calculating Machine by Blaise Pascal

Leibniz Wheel

ENIAC Computer

EARLY COMPUTING DEVICES

Joseph Jacquard Loom

Abacus

The abacus is an instrument used to perform arithmetic

calculations. Developed in ancient times, the abacus is still

used in China, Japan, and Korea. Difference Engine

complicated calculations were computed regularly by adept users until well into the 1960s.

Slide Rule Prior to the invention of the hand-held calculator, the slide rule was a standard tool for engineers and scientists. Operating on the principle that all mathematical computations may be carried out on sets of sliding scales, the device looks much like a heavily calibrated ruler with a movable midsection. The ENIAC midsection, called the sliding center scales, is engraved with Philadelphia has long been a center of high technology. fine lines to allow the user to align different logarithmic scales ENIAC (Electronic Numerical Integrator And Computer), the rapidly and efficiently. Multiplication, addition, subtraction, first fully electronic digital computer, was introduced at the division, squaring, cubing, extracting roots, and more University of Pennsylvania in 1946 and remained in service until 1955. ENIAC contained 18,000 vacuum tubes and required manual rewiring to be programmed.

Early DIAGRAMATICAL ILLUSTRATION OF A COMPUTER SYSTEM

Classes of Computer The followings are the 4 types of computers always found and use in different working places. 1. Micro-computer 2. Mini Computer 3. Mainframe computer 4. Super computer

Micro- Computer: This is the smallest type of computer and is generally designed for a single user. Micro- computer gets name from the tiny electronic component called the micro- which does the processing, sorting, arranging and the An ancient microcomputer transformation of data into a useful information . Micro computers are most often found in the office, hospital, schools, home, banks, airports and supermarkets.

An Electronic Data Recorder

Mini Computer: Mini computers are very big in size. They process and solve complex tasks. They do not have the complex processing power and memory of the mainframe computers. They are bigger than micro- computers. They are mostly found in banks, airports, hospital and different organizations.

Mainframe Computers: These computers are very fast, they have a complex (large) memory for storing and retrieving data and information. It allow many users (people working on the computer) at the same time. They are mostly used for performing complex calculations by the research organizations, industries etc.

Computer Card Key Punch

Supercomputer is the biggest of all. It processes multiple amount of data and also uses multiple processors for solving and carrying out its tasks.

IBM System/360 Mainframe Computer

Cm-5 Supercomputer

Examples of output devices include : printer, plotter, monitor, speaker, modem, webcam etc. The two major popular output devices are: Monitors and Printers. The result gotten through the monitor is called Softcopy. The result gotten through the printer is called Hardcopy The result gotten through the speaker is called Voicecopy.0

USES / FUNCTIONS OF OUTPUT DEVICES Monitor: Displays the result on the screen. Another name for monitor is VDU – Visual Display Unit. Cray Supercomputer OUTPUT DEVICES USES/FUNCTIONS OF MONITOR Performance Objectives I. VDU display information on television like screen. Pupils should be able to: II. VDUs can typically display up to 32 lines of writing i. State the meaning of output devices (text up to 80 characters across the screen). ii. Recognize a printer and monitor as III. Information can be displayed on the VDUs on a output devices screen that has been divided into Windows, to iii. State the uses of a monitor and select particular items. printer. IV. Characters can be coloured, italicize, double height and line spaced. OUTPUT DEVICES V. It is used for watching films. Output devices are machines through which the result of VI. It is used for correction and editing errors. processing is made available to the user. another computer or use any number of specialized output devices like speakers, digital cameras, projectors etc.

PROCESSING This part transforms data into a useful information. Once the data is in a computer, it is processed by the processor and its associated chips. Processors perform calculations and manipulations necessary to transform data into meaningful information. Also with the processor is the memory, which is used for storing data and programs while they are being used by the processor. OUTPUT Getting processed information out of the computer is the job You have already seen that computers can receive data, of output devices. The computer can display the data on a process it and display the results. However, computer can monitor screen of which there are several types. laos store data for future use. The processing is carried out in 1. Monochrome or White and Black the (CPU) which is the heart and the 2. Colour brain of any computer. 3. Flat Screen or Panel/LCD (Liquid Crystal Display) in the case of laptop computers. The CPU is made up of: 4. CRT (Cathode Ray Tube) in the case of desktop 1. The computers. 2. The Memory Unit 3. The Arithmetic and Logical Unit (ALU) You can also send data to a printer or plotter to make a paper copy, use the modem to send the data over a phone line to

that you can save it and retrieve it later. All computers use disks to store data magnetically. Each type of disk is used by its corresponding disk drive to read and write information. Floppy disks are used for easy and portable storage. Hard disks are used for more permanent storage of large amounts of data and programs for fast access.

PRINTERS Printers create paper copies called hardcopies of information sent from the computer system. The type of printer used with a particular computer system depends mainly upon the speed of printing and the quality of print required.

Types of printers Printers are divided into two STORAGE i. Impact Printer This is the process of saving information inside and outside ii. Non-impact printer the computer system. The computer system needs stored programs and data to carry out the processing. Small Impact Printer: amounts of data are stored on Flash Disk, CD ROM. These Strike the paper with pins. Impact printers are noisy when are called Backing Stores. printing and they allow multiple copies of documents to be made by using carbon paper between the sheets of paper. Where do you go if you want to keep the data into a permanent place? That’s what storage devices are for. Non Impact Printer Storage devices holds date permanently in the computer, so This forms the image without striking the paper. It includes desk or inkjet and Laser jet printers.

Examples of Impact printers: Dot Matrix Printer, Daisy Wheel Printer, Chain Printer, Drum and Barrel printer.

Examples of Non Impact Printer: Thermal Printer, Inkjet Printer, LaserJet Printer and Graph Plotter

Dot matrix

An output from dot matrix Daisy Wheel Printer

SPEAKER ii. It is also used for the production of hardcopies Speaker gives out sound from the computer system. (printouts) of pictures, drawings and graphs. iii. Objects can be displayed in two dimensions or as a solid object in three dimensions. iv. A variety of colours and intensities can be achieved depending on the number of points plotted. v. Scaling and dimensions can be inserted by the computer to produce a complete detailed plan of the designed object.

vi. Plotter produces a drawing of the design, this might Speaker be a graph, a line drawing or a picture.

USES/FUNCTIONS

i. Gives output from the computer in the form of

sound.

ii. Speakers’ control buttons can be used to high-low

or change the setting of sound effects.

PLOTTER

Plotter is an output device used for drawing and printing graphical lines.

USES/FUNCTIONS

i. Plotters are used for drawing two or three

dimensional drawings as used in engineering

designs concept.

The Flatbed plotter Plotters COMPONENTS OF A SYSTEM UNIT II Performance Objectives At the end of the lesson pupils should be able to: i. Identify the location of the disk drive ii. Explain the meaning of disk drive iii. List types of disk drives iv. State the functions and uses of disk drive v. State Dos and don’ts of using disk drives.

Drum plotter showing the different pens

IV. For retrieving and saving files.

DOS OF DISK DRIVES I. First eject the CD from the drive before shutting down the system II. Wipe the surface of the disk before injecting it into the drive. III. Keep the disk in a safe and warm place , preferably in its jacket. IV. Press the inject and eject button gently

DON’TS OF THE DISK DRIVES DISK DRIVES I. Don not shut down the system if the disk is still in Disk drives consist of floppy disk, CD ROM and Hard disk the drive drives. II. Do not allow any damage disk into your disk drive III. Do not allow any damage disk into your disk drive TYPES OF DISK DRIVES IV. Do not expose the drive to water and dust. I. Floppy disk drive V. Do not allow any unauthorized user to make use of II. CD ROM drive your disk drives. III. Hard disk drive STORAGE DEVICES USES OF DISK DRIVES Storage devices are tools used for storing and saving I. For storing information information inside and outside the computer system. II. For managing files and folders III. For exploring files and directories CLASSES OF TORAGE DEVICES I. Internal storage devices II. External storage devices

Internal storage devices : are devices used for saving data into the computer system eg. Hard disk.

External Storage devices: are storage devices used for saving data outside the computer system e.g CD Rom, Flash drive, Floppy disk etc.

TYPES OF COMPUTER STORAGE DEVICES i. Flash drive This is an external storage device used for saving information outside the computer system. It is measure in Megabyte and Gigabyte. Flash drive is a removable storage device. ii. Hard disk This is an internal storage device used for saving data inside the computer system. It is symbolized by C: . It is a non removable storage device.

Tape Streamers

Micro drives

THE FLOPPY DISKETTE Video disks can store voices, graphs and pictures Pupils should be able to: iii. DVD i. Identify a diskette This is a data-only format, much like a CD Rom disk. It can ii. Describe a diskette only read the content of DVD disk. iii. Mention types of diskettes iv. CD ROM CARE OF DISKETTE CD Rom can hold large amounts of removable data and can i. Do not expose the diskette to water and dust be mass-produced at a very low cost. The full meaning of CD ii. Always keep it in its jacket Rom is Compact disk read only memory. iii. Keep in a warm place iv. Always eject before shutting down the computer system v. Do not allow bad diskette into your diskette drive

Two floppy disk types : 5.25 and 3.5. The 3.5 format is considered superior, both because it stores more information and because its more rugged. The 3.5 disks have plastic case and sliding metal cover for the data window protect the disk better and the locking write-protect tab is more durable and convenient than the stickers you must place over the write – protect notch of the 5.25 disk.

Floppy disk drives are needed to place software on your computer and exchange data with other people. There are 1 1 currently two sizes of floppy disks: 5 /4 inch and 3 /2.

Family Size Diskette (Capacity in byte) IBM 5.25 360K IBM 5.25 1.2MB IBM 3.5 720K IBM 3.5 1.44MB Mac 3.5 400K

Floppy disk drives also called diskettes are magnetic storage media that are removable and easily transported from one place to another. They are inserted into a floppy disk drive. Floppy disk drives come in several sizes and storage capabilities. 1 SLOTTING 3 /2 DISKETTE INTO CPU DISKETTE DRIVE  Typewriter cannot hold and remember information for future use 1. First check to make sure that there is no  A computer is programmable floppy diskette in the drive.  Typewriter is not programmable 2. Make sure the magnetic side of the steel faces up BINARY SYSTEM 3. After this, slot in your diskette gently. Human data is a series of complex thoughts and ideas, but computer data is nothing more than a series of electrical TO EJECT YOUR DISKETTE DRIVE signals. To convert human data into a form the computer can Underneath your floppy drive is a small button called diskette understand , each number, letter, or any other input is eject button. It is the button you will press that will pull out converted into a specific compbination of electrical signals in your diskette for you. binary forma

Note: Do not eject the button when the floppy drive light is on. Wait until the light is off before you reject it.

Diffferences between computer and typewriter  A computer is completely electronic  Absence of electronic part s in typewriter  In computer functions are carried out with electronic signals  A computer can hold and remember information for future use