COMPUTER STUDIES (SS 1)

Scheme of work

Week	Topic
1	Writing the scheme of work/introduction
2-3	OVERVIEW OF COMPUTER SYSTEM ·        Definition of computer ·        Constituents of a computer ·        Computer hardware ·        Computer software ·        Characteristics of a computer
4	DATA AND INFORMATION ·        Definition of data and information ·        Differences between data and information ·        Examples of data and information
5-6	COMPUTING DEVICES 1(Pre-computer age to 19th century) ·        Features, components and uses of: Abacus, Slide rule, Napier’s bone, Pascal’s calculator, Leibniz multiplier, Jacquard’s loom, Charles Babbage difference and Analytical engine, Hollerith machine `
7-8	COMPUTING DEVICE II (20TH century to date) ·        Features, components and uses of: ENIAC, EDVAC, UNIVAC 1, Desktop PC, Laptop and Notebook computer, Palmtop computer.

TOPIC ONE: OVERVIEW OF COMPUTER SYSTEM

Definition of a Computer

A computer can be defined as an electronic machine (device) which under the control of a stored program accepts data, stores the data, processes the data and brings out the results as information.

Computer as an IPOS system

 

Computer performs 4 key operations on data

a. Input                                b. Processing     c. Output             d. Storage

Input: data are entered into the computer through the input unit. Data are raw facts that are to be processed into meaningful form.

Processing: Computer performs certain operations on data entered into it; the Central Processing Unit (CPU) handles this operation.

Output: The result of what has been processed will be displayed by the output device such as the monitor.

Storage: Inputted data and processed information are stored in the memory and permanent storage on the computer.

Constituents of a Computer system

The computer is referred to as a system because it is made up of several components that work together to enable it function properly. There are 2 main constituents of the computer system, these are:

•     The hardware
•       The Software

 

Hardware

These are the physical components of the computer system. They are the tangible parts that can be seen and touched. There are two major parts, namely:

·         The system unit

·         The peripherals

System unit: The system unit is the rectangular casing that houses (contains) several important components that controls the operation of the computer system such as the motherboard, CPU (Microprocessor), RAM, Sound card, video card, CD drive, Floppy disk drive etc. It also provides interface for connection of the peripherals.

Peripherals: These are the devices connected to the system unit for the purpose of input, output and storage operations. Examples of peripheral devices are keyboard, Mouse, Monitor, Printer, Scanner, DVD, CD, USB flash drive etc.

Software

The software is a term used to describe the collection (or set) of programs that can be run on a computer system. A program is a set of instructions that tells the computer what to do, when to do it and how to do it.

There are two types of software, these include:

• System software
• Application software

System software: This software controls the computer hardware and the internal operations of the computer system. Examples include Windows OS (Windows XP, Windows ME, Windows Vista, Windows 7, Windows 8, Windows 10), Linux OS(Redhat, Fedora, Ubuntu etc.),  MAC OS etc.

Application software: These are software that enables the user to perform specific operation or task on the computer. Examples include:

Application software (packages)	Functions / Uses
MS Word, WordPad, WordPerfect	Used for word processing
MS Excel, Lotus1-2-3, Quattro Pro	Used for spreadsheet, calculation and analysis
Corel draw, Paint, Photoshop, PageMaker, Corel Graphics	Used for graphic works
Front page, Publisher, Dreamweaver, cold fusion	For web designing
MS Access, Oracle, Postgre sql, Fox pro, Dbase, Ingress, MySQL	For database management
MS outlook, Outlook express, MS exchange, Sendmail	For email management
MS PowerPoint, Impress, Prezi, Harvard Graphics	Used for presentation of seminars and lectures
Maths, MATLAB, SPSS, Mintab	Create and edit mathematical formulae/statistical analysis
Internet explorer, Mozilla firefox, chrome, Opera mini, UC browser, Netscape Navigator, Safari ,  Mosaic,	Internet/Web browsing

Characteristics of a Computer

• ·         Speed: Computer performs its data processing operation at a very high speed. The speed of the computer is measured in Hertz (Hz). A computer with speed rating of Mega Hertz (MHz) can perform millions of cycle of operation per second.

• ·         Accuracy: Computer gives accurate result as long as the correct data is keyed into it.

• ·         Versatility: computer can be used to perform various kinds of task e.g. graphic design, word processing, web development etc.

• ·         Reliability/Durability: Computers do not get tired like human; they can work continuously for days and weeks without any error.

• ·         Memory and storage: Computer can store large amount of data and information. The capacity of the memory/storage device is measured in bytes. A byte is a group of eight bits. A kilobyte (KB) is 1024 bytes. A megabyte (MB) is 1,000,024 bytes.

• ·         Programmable: The computer hardware is useless without the program that controls it. Thus, all tasks and activities performed by a computer are made possible by means of a program.

• ·        It is electronic in nature

 

TOPIC TWO: DATA AND INFORMATION

Data

Data are raw facts and figures without any added interpretation. Data can be defined as a representation of facts or concepts in a formalized manner which should be suited for interpretation or processing by human or electronic machine. Examples of data include:

•  Symbols: $, @, &, /, # etc.

•  Figures/Numbers: 1, 2, 34, 0.12 2 etc.
• Alphabets: A-Z or a-z
• Words: Tunde, Facts, Ibadan etc.

 Information

Information is an organized or classified data which has some meaningful values for the receiver.  It can also be defined as the processed data on which decisions are based. Examples of information include:

• Computer is a representation of modern life
•  2 x 7 = 14
• 10% of N1000 = N 100

Sources of data and information

Sources of data

Data are used for information generation and this can be obtained from different sources. Some of the sources of data include:

• Observations 
•  Questionnaires
• Interviews, survey and fieldwork 
•  Registrations 
•  Experiments 
•   Form filling

 Sources of information

Information can come from virtually anywhere — media, blogs, personal experiences, books, journal and magazine articles, expert opinions, encyclopedias, database, television, newspapers and web pages — and the type of information you need will change depending on the question you are trying to answer.

Differences between data and information

Data	Information
Data is used as input for the computer system.	Information is the output of data.
Data is unprocessed facts and figures.	Information is processed data.
Data doesn’t depend on Information	Information depends on data.
Data is not specific.	Information is specific.
Data doesn’t carry a meaning	Information must carry a logical meaning.
Data is the raw material.	Information is the product.
Data cannot be used for decision making.	Information is used for decision making

Qualities of good information

•   Relevance: It must be suitable for the purpose it is required for.
•    Accurate: It be free from errors
•     Availability: It should be easy to obtain or access
•     Timely: It should be available at the right time
•     Comprehensive/Completeness: It should contain all necessary details
•   Reliability: It should come from a reliable source.

TOPIC 3: COMPUTING DEVICES I

• ·         Abacus

Features and components

Abacus was invented around 500 BC. It was made up of strings or wires, frames and beads. Modern Abacus uses sliding beads in columns that are divided into two by a center bar. The upper part is called the heaven and each of the two beads (representing the two hands) is worth 5 when moved to the center. The lower part is called the “earth”, where each of the 5 beads (representing the 5 fingers) is worth 1 when moved towards the center. The Abacus is really just a representation of the human fingers.

Use

For addition and subtraction

• ·         Napier’s Bone

Features and components

John Napier in 1617 invented the Napier’s bone. The device involves a collection of moveable numbered rods and a board.

Use

Used to perform multiplication

• ·         Slide rule 

     Features and components 

William Oughtred invented the slide in 1632. The Slide rule is a mechanical analog computer. In its most basic form, the slide rule uses two logarithmic scales to allow rapid multiplication and division of numbers.

Uses

The slide rule is used mainly for multiplication and division, and also for "scientific" functions such as roots, logarithms and trigonometry, but usually not for addition or subtraction.

• ·         Pascal’s calculator

Features and components

Blaise Pascal invented the Pascal’s calculator otherwise called PASCALINE in 1642. It is a gear or dial driven (just as that on analogue telephone) calculating device.

Use

It could only be used for addition and subtraction operations. It’s use is evident in odometer and electricity meter.

• ·         Leibniz multiplier

Features and components

Leibniz multiplier or (Stepped Reckoner) was invented by Gottfried William Leibniz in 1671. It was an improvement on the PASCALINE. It contains a special kind of gear called “Leibniz wheel”.

Uses

It could add, subtract, multiply and divide.

• ·         Jacquard’s loom

Features and components

In 1801, Joseph Marie Jacquard invented the Jacquard’s loom. This machine was controlled by a number of punched cards, put together into a continuous sequence.

Use

Used for producing fabrics with beautiful patterns

• ·         Difference engine

Features and components

In 1822, An English mathematics professor called Charles Babbage invented the Difference engine. It was composed of 25000 parts, weighed 15 tons and stood 8 feet (2.4m) high.

Use

Used for calculating differential equations.

• ·         Analytical engine

Features and components

In 1832, Charles Babbage designed another machine called Analytical engine which was deemed to be the first mechanical computer. The machine was steam-powered, though never completed, outlined the basic elements of a modern day general purpose computer. It contains input in the form of punched card containing operating instructions and a "store" for memory of 1,000 numbers of up to 50 decimal digits long. It also contained a "mill" with a control unit that allowed processing instructions in any sequence, and output devices to produce printed results. Augusta Ada, Countess of Lovelace (1815-1842) created the instruction routines to be fed into the computer, making her the first female computer programmer.

Use

It could store 1000 numbers of up to 50 decimal digits long. It was programmable.

•  ·       Herman Hollerith machine

Features and components

Herman Hollerith invented the Herman Hollerith machine which used punch card to store information which he fed into the machine to compile the results mechanically.

Use

It was used for collating, sorting and summing the data gotten from 1980 US census.

TOPIC FOUR: COMPUTING DEVICES II

• ·        ENIAC

In 1946, John Mauchly and J. Presper Eckert completed the ENIAC (Electronic Numerical integrator and Calculator). It was the first general purpose computer. ENIAC contained 18,000 vacuum tubes, weighed 30 tons, occupied 1800 square feet of floor space and required 160 kilowatts of electrical power. The ENIAC used punched card for input and output. ENIAC was used by US for hydrogen bomb project and programming.

• ·        EDVAC

Features and components

The EDVAC (Electronic Discrete Variable Automatic Computer) is the successor of the

ENIAC and was made by the same designers: John Mauchly and Presper Eckert in 1949. 

Unlike its predecessor the ENIAC, it was binary rather than decimal. It was the first 

designed stored  program computer with memory capacity of 1000 words (later set to

 1,024 words, thus  giving a memory, in modern terms, of 5.5 kilobytes). It contains 

6,000 vacuum tubes and consumed 56 KW of power and covered 490 square feet of 

floor space.

• UNIVAC 1

Features and components 

The UNIVAC 1 (Universal Automatic Computer 1) was invented by John Mauchly and 

Presper Eckert in 1951. The machine was 25 feet by 50 feet in length, contained 

5,600 tubes, 18,000 crystal diodes, and 300 relays and had an internal storage capacity 

1,000 words  or 12,000 characters. It utilized a Mercury delay line, magnetic tape, and

 typewriter output.  Magnetic tape was still used for input and output. It was the 

first commercial computer.

Assignment

State the features and components of the following devices

·        Desktop Personal Computers

·        Laptop and Notebook Computers

·        Palmtop computers

TOPIC 5: INPUT DEVICES

These are the hardware devices that are used for entering data and instructions into the computer
system. The input devices allow human to interact with the computer system. The following 

     are some examples of Input devices:

Keyboard: Most important input device. The keyboard is very much like a typewriter keyboard 

      with a few additional keys. The keys when pressed send an input signal into the computer. 

Mouse: A mouse is a small object you can roll along a hard or flat surface. It controls the movement 

of the cursor on a display screen.

Light pen: An input device that utilizes a light-sensitive detector to select, create and modify object 

on a display screen.

Touchpad: A touchpad is used for pointing on a computer display screen. It works by sensing the 

user’s finger movement and downward pressure. It is often rectangular in shape and found mostly

 on laptops. It is an alternative to mouse.

Touch screen: It allows the user to operate / make selections by simply touching the display screen. 

The display screen is sensitive to touch of a finger or stylus. Widely used on ATM machines and 

most mobile phones.

Microphone: A device that is used to capture and record sound.


Bar code reader: These are photoelectric scanners that read bar codes printed on product containers.

 They are generally used in super markets.

Scanner: Scanner reads texts, images or illustrations printed on paper and translate the information

 into a form that the computer can use. It works by digitizing an image.

Magnetic Ink Character Recognition (MICR): MICR can identify character printed with a special

 ink that contains particles of magnetic material. This device is widely used in banking industry. 

Optical Mark Recognition (OMR): Also called mark sense reader is a technology where an OMR 

device senses the presence or absence of a mark, such as pencil mark. OMR is widely used in tests
such as aptitude test.

Joystick: Is an input and pointing device used in computer games.

Digital camera: An input device used to capture images and moving pictures.

Differences between Mouse and Keyboard

 


  

Keyboard

  

Mouse 

 

  

Used to enter instructions

  

Used to point and select

 

  

Keys are pressed 

  

Buttons are clicked

 

  

Combination of keys can be pressed

  

Left or right button is clicked

 

  

Cannot drag and drop text

  

Drags and drops text

 

  

It has keys

  

It has buttons

 

  

Requires no mouse pad

  

Requires a mouse pad

 

Assignment

List and briefly briefly explain ALL set of keys on the keyboard. Hint: Alphabet keys