A JOURNEY INTO THE WORLD OF COMPUTER TECHNOLOGY

Designed and brought 4u By

Aloyce John Kalunde

+255 783700083

Understand a Computer

1. A computer is a machine.
2. A computer has electronic property.
3. A computer accepts, processes and stores data.
4. A computer performs tasks automatically.
5. A computer is intended to give out useful outcomes (information).

So, what is a Computer?

A computer is an electronic machine which accepts, processes and stores data automatically following some instructions to give useful output.

Important Concepts

The following five concepts are important for the beginner to understand at the beginning of the course

1.  software
2.  Hardware
3.  Information Technology (IT)
4.  The server computer
5.  The client/terminal computer

Hardware is a physical part of the computer system.  It is any computer accessory you can see, touch and feel.

Software is a set of instructions which tells the computer how to do things. Software is also called a program.

Information Technology (IT) manages the technology and computer infrastructure that drives an organization's computer-based business systems.

The Server Computer, A computer or device on a network that manages network resources is a SERVER. For example, a file server is a computer and storage device dedicated to storing files. Any user on the network can store files on the server.

Concepts: The Client/Terminal Computer

               i.                  Intelligent Terminal is a computer in the network with built-in processing capability but no local disk or tape storage.

             ii.                  A dumb terminal is a computer in the network, which is only a communication device with another computer.

Questions

1. What is meant by the term ‘software’?
2. What does it mean by ‘hardware’? Give some examples of hardware.
3. What is IT short for?
4. What does the term IT mean?
5. Differentiate Server and Client computers
6. Define computer

Types of Computers

There are five (5) Main Types of Computers

The main types of computers are classified in the following categories:

                     i.            Minicomputer

                   ii.            Super computer

                  iii.            Personal computer

                 iv.            Laptop computer

                   v.            Palmtop computer

1. The Mainframe Computer offers the ultimate processing power and storage capability.

1. Is the most bulky one (very big in size)
2. Is the most expensive computer
3. Has the largest memory capacity and the highest processing speed of information
4. Is used in large scale organization to process a bulk of information.

The Minicomputer is smaller than Mainframe Computers. Its functions is almost as the same as the Mainframe computer

Minicomputers have the following properties:

                     i.            Very powerful and expensive

                   ii.            Used in medium scale organizations where it is too expensive to use mainframe computer

2. The Super Computer is a computer that leads the world in terms of accuracy, particularly speed and precision. Super computers are used in Military and Research institutions with the following characteristics:

                     i.            Very Accurate

                   ii.            High processing speed

3. The Personal Computer (PC) this is a computer that is small enough to fit on a desktop and the least expensive enough to be bought by an individual for personal use.

4. The Laptop Computer is a small-size PC that can use battery power and be carried around. Is a portable computer, briefcase size. It is used by people in the move, such as sales representatives and business travelers. As the ‘desktop’ PC, It can suit your personal requirements.

                     i.            They are more expensive than desktop PCs

                   ii.            They are able to operate in low power consumption.

5. The Palmtop Computer (PC)

                     i.            Are even smaller than Laptops

                   ii.            Are used in mobile business and social activities

Computer System Components

Computer Hardware

This is a physical part of the computer system. Its Hardware is grouped into four (4) categories, namely:

                     i.            Input Devices.

                   ii.            Central Processing Unit (CPU).

                  iii.            Storage Devices.

                 iv.            Output Devices.

1. Input Device is any machine that feeds data into a computer. For example, a keyboard is the most popular input device. Input devices other than the keyboard are sometimes called alternate input devices. Mice, trackballs, and light pens are all alternate input devices.

2. Central Processing Unit (CPU) is referred to as the brains of a computer. It contains two (2) basic components:

i. Control Unit (CU)- instructs the rest of the computer system on how to follow a program instructions

ii. Arithmetic Logic Unit (ALU) –performs both Arithmetic and Logical operations.

NB: The speed of the CPU (processor) is measured in Hertz (Hz) unit.

3. Output Devices displays the processed information to the user (shows what is going inside the computer to the outside) examples of them are; Monitor, Printer, and Speakers

Output Devices:

The Monitor, Most desktop computers use a monitor with a Cathode Ray Tube (CRT) and most notebooks use a Liquid Crystal Display (LCD) monitor. To get the full benefit of today's software with full color graphics and animation, computers need a color monitor with a display or graphics card.

The Printer takes the information from your computer and transfers it to paper or a hard copy. There are many different types of printers with various levels of quality. The three basic types of printer are; dot matrix, inkjet, and laser. Dot matrix printers work like a typewriter transferring ink from a ribbon to paper with a series or 'matrix' of tiny pins. Ink jet printers, work like dot matrix printers but fires a stream of ink from a cartridge directly onto the paper. Laser printers use the same technology as a photocopier using heat to transfer toner onto paper

Storage Devices, They are grouped into two types namely:

(a) Temporary (Primary) Memory, for instance, RAM (Random Access Memory)

                     i.             where information to be processed is held

                   ii.            Instructions on how to process that information is also held

NB: anything store in RAM will be lost when the power is turned off.

(b) Permanent (Secondary) Storage Devices Store information permanently for future use. The most popular Permanent Storage Devices are the Hard Disks (internal and external), compact disks (CDs), floppy diskettes, removable disks (flash disks, tape drives etc.

Types of Computer Memory

1)      RAM

                                 i.            Random Access Memory

                               ii.            The main working memory of the computer

                              iii.            Measured in Megabytes

2)      ROM

                                 i.            Read Only Memory

                               ii.            Contents are ‘hard wired’ and cannot be altered

                              iii.            Often contains software used to get the hardware to talk to the operating system

Peripheral Devices

Computer peripherals are any electronic devices that can be hooked up to a computer other than the standard input-output devices. Peripheral devices include speakers, microphones, printers, scanners, digital cameras, plotters, and modems.  Peripherals often require special software packages called "drivers". These drivers are usually included with the peripheral at purchase time.

Computer Performance

Factors Which Impact on a Computer’s Performance ARE

                                 i.            The higher the processor speed, the faster the computer

                               ii.            As a rule the more memory you have (RAM), the faster the PC will appear to operate

                              iii.            The more programs which are running at the same time, the slower each one will run

                             iv.            The lower the hard disk size, the slower the computer

Measuring Computer Storage Capacity

A Bit: All computers work on a binary numbering system, i.e. they process data in one's or zero's. This 1 or 0 level of storage is called a bit

A Byte: A byte consists of eight bits

A Kilobyte: A kilobyte (KB) consists of 1024 bytes, approx 1,000 bytes

A Megabyte: A megabyte (MB) consists of 1024 kilobytes approx 1,000,000 bytes

A Gigabyte: A gigabyte (GB) consists of 1024 megabytes approx 1,000,000,000 bytes

A Terabyte: A terabyte (TB) consists of approx 1,000,000,000,000 bytes

Storage Capacity Measurement

                              iii.            1 Byte              = 8Bits

                             iv.            1 Character        = 1Byte

                               v.            1 Kilobyte (KB)   = 1024 Bytes

                             vi.            1Kilobyte            = 1024 Character

                            vii.            1Megabytes (MB) = 1024KB

                          viii.            1Gigabytes (GB)   = 1024MB

                             ix.            1Terabytes (TB)    = 1024GB

                               x.            1Petabytes (PB)    = 1024 Terabytes

Computer Software Is a set of instructions which tells computer how to do things.

Operating System

                                 i.            Required to make the computer work

                               ii.            Translates between humans and the computer hardware

Applications Software such as a word-processor, spreadsheet or database

Operating System Software

An operating system is the link between you and the hardware/software

                                 i.            DOS

                               ii.            Windows 3

                              iii.            Windows 95

                             iv.            Windows 98

                               v.            Windows Millennium

                             vi.            Windows NT

                            vii.            Windows 2000

                          viii.            Windows XP

                             ix.            Others Operating systems(non-microsoft) are Macintosh and  Linux family including RedHat, Debian, Ubuntu, Fedora etc