Section 1: Fundamentals of Hardware and Software

Question 1

The major functions of a general-purpose system are:

Answer 1

Input: involves obtaining data for processing

Processing: involves the manipulation of data to produce information. Manipulation means multiplying, adding, subtracting, dividing, sorting etc.

Output: involves sending information to users.

Storage: involves keeping the data on electronic storage.

Question 2

What is the Central Processing Unit (CPU)?

Answer 2

The CPU is also called the processor. It takes raw data, follows a set of instructions (programs) and converts it into information. The CPU consists of two smaller units known as the control unit (CU) and the arithmetic and logic unit (ALU).

Question 3

What is the Control Unit (CU)?

Answer 3

This is the main part of the CPU. It directs and coordinates all activities within the CPU. It determines the sequence in which instructions are executed. The CU executes an instruction by performing the following steps:

1. Fetching the instructions from memory
2. Decoding the instructions
3. Fetching the data required by the instructions from memory
4. Sending the data and instructions to the ALU for processing
5. Sending the data to memory after processing

Question 4

What is the Arithmetic and Logic Unit (ALU)?

Answer 4

The ALU performs all the arithmetic and logic functions in a computer. The arithmetic operations include addition (+), subtraction (-), multiplication (*) and division (/).

Question 5

What is the Main Memory?

Answer 5

Main memory is also called computer memory, immediate access storage (IMAS/IAS) or primary storage. This unit of memory is directly accessible to the CPU. It holds data and instructions that the computer is processing at the time.

Question 6

What is the Secondary Storage?

Answer 6

These devices are used to store data and instructions when they are not being processed. Secondary storage is more permanent than main memory, since data and instructions are not lost when the power is turned off. It is also much cheaper than primary storage and is unlimited since you can have as much of it as you can afford. The most commonly used auxiliary storage devices are magnetic storage (tapes and disks), optical storage (CD ROM, CD-R, DVD-ROM, DVD-R and DVD-RW and solid state memory (flash memory and USB drives).

Question 7

What are Peripheral Devices?

Answer 7

Peripheral devices are any device controlled or monitored by the CPU. It includes both input and output devices.

Question 8

What are Input Devices?

Answer 8

Input devices are any device that is used to put data and instructions into the computer. Some commonly used input devices are keyboard, mouse, joystick, digital camera, scanners, barcode readers and magnetic strips.

Question 9

What are Output Devices?

Answer 9

Output devices are any device that is used to get information out of a computer. Some commonly used output devices are VDU or monitor, printer, plotter, speakers and multimedia projector.

Question 10

What is the Primary Storage?

Answer 10

This is a group of silicon chips that resides on the computer’s motherboard (main circuit board). Primary storage consists of two types of memory chips: RAM and ROM chips. A memory chip is an integrated circuit (IC) made up of millions of transistors and capacitors.

Question 11

What is RAM?

Answer 11

Random Access Memory is a chip that is used to hold data and instructions (programs) temporarily while processing is taking place using that data and program. It also holds the data that results from processing – data that is waiting to be output or stored in a secondary storage device. RAM is volatile i.e. it is temporary and changeable. If the power is turned off or the computer is rebooted (started up again) all the information held in RAM will be lost.

Question 12

What is ROM?

Answer 12

Read Only Memory is a chip that holds data and instructions necessary for starting up the computer when it is switched on. It is used to store system-level programs such as the BIOS (Basic Input Output System) program.

Question 13

What are the Variations of ROM?

Answer 13

Programmable ROM (PROM) : This type of ROM can be programmed only once using special equipment. It is useful for companies that want to make their own ROMs from software they write themselves. If they change their code they can create new PROMs without requiring a ROM manufacturer.

Erasable programmable ROM (EPROM) : This type of ROM can be erased and reprogrammed, which makes it more useful than a PROM. EPROM chips are programmed in the same way as PROM chips. Data is erased from this chip by exposing it to ultraviolet light of a specific frequency for a specified period of time.

Question 14

What are Units of Storage?

Answer 14

Memory is made up of bistable devices. Bistable means the components that make up memory can be set to one of two states either on or off. These two states are represented using binary digits- 0 for off and 1 for on. As such, the smallest unit of storage of memory is called a binary digit (bit). The amount of data and instructions that can be stored in primary storage or secondary storage media is measured in bytes.

Question 15

What is a byte?

Answer 15

A byte is made up of a combination of 8 bits and has the capacity to represent one character i.e. a letter, a number, a symbol, a punctuation mark or a blank space.

Question 16

What is a Word?

Answer 16

A word is the amount of bits the computer can process in one operation.

Question 17

What is a Word size?

Answer 17

A word size or word length is the number of bits in a word.

Question 18

Larger Units of Storage

Answer 18

1. Kilobyte
2. Megabyte
3. Gigabyte
4. Terabyte
5. Petabyte
6. Exabyte
7. Zettabyte
8. Yottabyte

Question 19

Secondary Storage Media

Answer 19

Secondary storage devices are chosen for a particular use based on their:

1. Storage capacity (how much data the device can store)
2. Access speed ( the time needed to locate the data and transmit it to the CPU)
3. Portability ( ability to be easily removed and used on another system)
4. Cost
5. Size (necessary for storage on shelves or portability)

Question 20

Magnetic tape

Answer 20

A magnetic tape looks like an audiocassette tape. Tapes may come in different sizes. It is used mainly to backup hard disks because it can store large amounts of data at a low cost. Accessing data on a tape is very slow since data is stored sequentially. Sequentially means that data is retrieved in the order which it was stored.

Question 21

Magnetic disks (Floppy disk, Hard disk)

Answer 21

All magnetic disks provide direct access to stored data. This means that you can go directly to specific piece of data without having to access any other either before or after the data you want.

Question 22

Floppy disk

Answer 22

This is also called a diskette. It is a removable, flexible plastic disk, coated with a magnetisable material. The floppy disk is used to store and transfer small amounts of data between computers. Data and information is written to or read from the disk by a read/write head in the disk drive held in the system unit. Data is stored on both sides of a diskette on tracks and sectors. Before data is stored on a floppy disk, it needs to be formatted. Formatting means writing electronic information on the disk so that the computer can recognize the disk as a valid storage device where data can be stored.

Question 23

Hard disk

Answer 23

A hard disk is a thin but rigid, inflexible disk made of highly polished metal. There are different types of disk: moveable head, fixed head and external. Moveable head hard disks have one read/write head per disk. Fixed head disks have a read/write head for every track on the disk.

Question 24

External Hard Disks

Answer 24

The external and removeable hard disks are portable hard disks that are connected to the system unit. External hard disks have very large storage capacities. They are used mainly by very large computers. Hard disks can store much more data than floppy disk and optical disks and access and transmission of data is faster.

Question 25

Optical Disks

Answer 25

Optical disks are disks that are read by laser lights. They are made from plastic. The data is stored on layers inside the plastic. CDs and DVDs are the two main types of optical disks.

Question 26

USB Flash drive

Answer 26

USB Flash drives are storage devices which consist of a small circuit board encased in a plastic or metal casing built with a USB interface. They are typically small, lightweight, removable and rewritable. Flash drives are more compact, generally faster, hold more data and may be more reliable (due to their lack of moving parts) than floppy disks.

Question 27

Flash Memory Cards

Answer 27

They are a special type of EPROM that can be erased and reprogrammed in blocks instead of one byte at a time. They are used in PDAs (personal digital assistants), laptop computers, digital audio players, digital cameras, mobile phones and video game consoles.

Question 28

Device Interfaces

Answer 28

These are connectors and cables used to transfer data from the CPU to input, output and storage devices. There are different standards or technologies used to design these devices. Three main standards used are:

1. SCSI
2. IDE
3. SATA

Question 29

Small Computer System Interface (SCSI)

Answer 29

It is a set of standards for physically connecting and transferring data between computers and peripheral devices. SCSI is most commonly used for hard disks and tape drives, but can connect a wide range of other devices, including scanners and CD drives.

Question 30

Intelligent Drive Electronics or Integrated Drive Electronics (IDE)

Answer 30

This interface is used specifically for mass storage devices, in which the controller is integrated into the disk or CD-ROM drive.

Question 31

Serial Advanced Technology Attachment (SATA)

Answer 31

This is a computer bus primarily designed for the transfer of data between a computer and mass storage devices such as hard disks drives and optical drives.

Question 32

Optical Mark Reader (OMR)

Answer 32

OMR detects the position of marks on paper. OMRs are used for correcting multiple choice examinations, analyzing data from surveys, counting election ballots and validating lottery tickets.

Question 33

Magnetic Ink Character Recognition (MICR)

Answer 33

MICR is mainly used by the banking industry to read cheques.

Question 34

Optical Character Recognition (OCR)

Answer 34

This is an optical scanner which utilizes special software to read characters from paper. It is used in the legal service, postal service, utility and financial companies and by immigration officers at airports.

Question 35

Mouse

Answer 35

The mouse has a ball underneath, which rolls and determines the direction of the cursor, and buttons which allow the user to make selections.

Question 36

Joystick

Answer 36

This device is used to control movement of the cursor or other objects on the screen by operating a small lever. It is used mainly for playing games, but it is also used with scanners at hospitals.

Question 37

Barcode Readers

Answer 37

Barcode readers give fast error-free data entry into the computer. It is a fast method of recording the sales of items. Barcode readers are used in supermarkets, libraries, research, airports, postal services and warehouses.

Question 38

Point of Sale (POS)

Answer 38

This is the combination of a barcode reader and computerized cash register. It is usually found in retail outlets.

Question 39

CPU Specifications

Answer 39

1. Types:
   * Make / Brand: Intel or AMD
   * Models: Pentium, Athlon, Celeron, Duron etc.
2. Speed: Gigahertz (GHz) ranging from 4 GHz up
3. word size: How many bits it can input/output and process at a time, 32-bit or 64-bit

Question 40

Hard Disk Drive (HDD) Specifications

Answer 40

• Interface connector/controller: PATA Parallel ATA or SATA Serial ATA
• Capacity: Gigabytes(GB) ranging from 80GB to 500GB
• Speed: Revolutions /rotations per minute (rpm) usually 7200 rpm for desktops and 5400 rpm for laptops

Question 41

Software

Answer 41

Software is the name given to all programs that computers use to perform different tasks.

There are two main categories of software:

1. Application software
2. System software

Question 42

Application software

Answer 42

Application software can also be referred to as Application packages. These programs are developed to perform specific tasks or solve a particular problem. Application software includes entertainment software such as games, home or personal software such as CD-ROM encyclopedias, productivity software such as word processing, spreadsheet packages and graphics.

Question 43

System software

Answer 43

These are programs that manage and support the resources and operation of the computer system. They enable the running of application software and the management of the system resources. System software includes operating systems, utility programs and language

Question 44

Operating system (OS)

Answer 44

An operating system is a set of programs that controls the operation of a computer. The computer cannot work without the operating system software. As soon as the computer is switched on the operating software on the computer is activated and loaded into main memory. The process of loading the operating system software into memory is called booting. Some operating systems used in computers are Windows 7, Windows Vista, Windows XP, Linux, UNIX and the Macintosh Operating System (e.g. MAC 0SX).

Question 45

Functions of the Operating Systems

Answer 45

1. Managing computer resources
2. Managing files and memory
3. Maintaining security
4. Managing tasks (processes) : It allows the computer to facilitate multitasking, multiprogramming and multiprocessing.

Question 46

Multitasking

Answer 46

Allows the computer to appear to perform many tasks simultaneously (at the same time)

Question 47

Multiprogramming

Answer 47

Allows the computer to appear to run more than one program at the same time, although at a specific time the CPU is dealing with only one instruction for one of the several programs being run.

Question 48

Multiprocessing

Answer 48

Allows more than one program to run at the same time by linking two or more computers or processors which can then work on different programs or different parts of the same program at the same time.

Question 49

Processing modes

Answer 49

The OS also facilitates different processing mode that are selected based on its suitability for the job to be performed. There are four modes of processing:

1. Time –sharing
2. Batch processing
3. Real-time processing
4. Online processing

Question 50

Time –sharing

Answer 50

This mode is used in multi-access systems where a single CPU is shared by several users using individual terminals. This method of processing makes the user believe they have continuous access to the CPU when in fact each user is given a time slice (small amount of processing time) in turn. This mode of processing is used at universities where students and lecturers are allowed access to a central CPU on a mainframe via different terminals throughout the campus.

Question 51

Batch processing

Answer 51

In this mode the programs and data are collected together in a batch queue before processing starts. The program and data collected is called a job. Usually jobs are stored during working time and executed when the computer is least in use (during the night). This is done in this manner since it does not require human interaction during processing, once the batch starts it continues until it is done or an error occurs. This mode is suited for payroll processing, processing utility bills and credit card billing.

Question 52

Real-time processing

Answer 52

In this mode the system is automatically updated when a change or transaction is made. It is interactive, allowing the user and the system to be in constant communication with up-to-date information. This mode is suitable for stock systems, airline booking systems, electronic funds transfer systems and control systems.

Question 53

Online processing

Answer 53

A system in this mode has access to a network. Unlike the real-time processing system, an online processing system is not updated automatically, so information is not always current and must be updated frequently.

Question 54

User Interfaces

Answer 54

1. Command driven interface
2. Menu driven interface
3. Graphical user interface (GUI)

Question 55

Command driven interface

Answer 55

This type of interface is used in a DOS operating system. To communicate with the computer, the user has to type a command in codes or words when prompt on the display screen. E.g. C :> dir tells the OS to list all the files on the hard drive.

Question 56

Menu driven interface

Answer 56

To communicate the user can either use the mouse or arrow keys to make a selection from a menu which contains commands e.g. Print, Save As, Open. There are two (2) types of menus:

• Pull-down menu – usually drops down from the menu bar when it is clicked.
• Pop-up menu – pops up from nowhere when the right mouse button is clicked.

Question 57

Graphical user interface (GUI)

Answer 57

This interface is also called WIMP (windows, icons, menus and pointing devices). To communicate with the user, it uses buttons, icons, menus and keystrokes to choose commands, start programs and see lists of files and other options. Icons are small pictures that represent programs, folders, files, tasks etc. In a The GUI all objects that are related to each other are shown in a window. More than one window can be opened on the desktop at the same time. The desktop is common visual background which appears on the display screen when the computer has finished booting.