In this unit you shall be introduced to the concept of a computer. The unit explores the definition and parts of the computer. It puts emphasis on the input, process, storage and output parts of the computer. The unit emphasises the concept of a computer as a system rather than a simple entity of processing. The difference between data and information shall also be covered.
By the end of the unit the student should be able to:
Define the term computer
Explain the concept of a computer as a system
Describe the functions of different parts of the computer system
Name various input and output devices.
Give the functions of various storage devices.
What is a Computer?
A computer is an electronic device that stores, accepts data, retrieves data, processes data and gives output according to a set of instructions. Business dictionary defined a computer as a generalpurposemachine, commonly consisting ofdigitalcircuitry, that accepts (inputs),stores, manipulates, and generates (outputs)dataas numbers, text,graphics, voice,videofiles, or electricalsignals, in accordance withinstructionscalledaprogram
Hardware is the collection of physical elements that constitutes a computer system. Computer hardware is the physical parts or components of a computer you can touch and see, examples of computer hard ware include monitor/screen, mouse, keyboard, hard disk drive (HDD), graphic cards, sound cards, memory, motherboard, and so on. All these are physical objects that are tangible.
Software: Software is any set of machine-readable instructions that directs a computer's processor to perform specific operations. Software refers to instructions that can be stored and run by hardware. A combination of hardware and software constitutes a usable computer system
User: An individual who uses acomputer. This includes expert programmersas well as novices. Anend useris any individual who runsanapplicationprogram. Usersgenerally use a system or a software product without the technical expertise required to fully understand it.
Main Hardware Components of the computer
Figure 1 a: The structure of the computer
(Adapted from http://ourjobs123.blogspot.com/2014/10/Computer-Basics-for-Bank-online-Aptitude-Tests.html)
This is the equipment that makes up a computer system (physical components).
Many of these parts are contained within the computer’s case.
Other parts are external but connected to the computer (peripheral devices). These allow data to be entered (input) and retrieved (output) and stored.
Internal hardware components
External Hardware components
These are devices which help you to interact with the computer by entering data and commands into the computer system. Examples of input devices are mouse and keyboard.
Processing devices (processor)
Output devices (monitor, speakers and printer) display data
Storage devices (memory sticks and disks) hold data
The processing device: Central Processing Unit (CPU)
The part of the computer performs the bulk of data processing operations is called the central processing unit
“Brain” as well as “heart” of computer system
The chip or chips at the heart of a computer that enable it to process data.
It is very easy to replace because it is inserted into the socket and is not soldered onto the motherboard
A computer may contain more than one CPU and is called a MULTIPROCESSOR.
The CPU is made up of four major parts:
Memory: An area within a computer system that holds data waiting to be processed.
Control unit: supervises the transfer of information among the registers and instructs the ALU as to which operation to perform by generating control signals.
Arithmetic logic unit (ALU)
Performs computation and comparison operations
Set of registers
Storage locations that hold inputs and outputs for the ALU
Stores intermediate data during the execution of instructions;
Magnetic – Storage devices use disks or tapes that are coated with magnetically sensitive material
Optical – Storage devices that use laser beams to read patterns etched into plastic disks
CD-ROM Discs and Drives
CD-ROM stands for Compact Disc-Read Only Memory.
CD-ROM drives cannot write data to discs.
They are capable of storing 650 MB of data.
They are used for storing operating systems, large application programs, and multimedia programs.
CD-R and CD-RW Discs
Discs can be read and written to
Discs are erasable
Discs can be written to many times
CD-RW drives are capable of reading, writing, and erasing data
DVD-ROM Discs and Drives
DVD stands for Digital Video Disc.
DVD technology is similar to CD-ROM technology.
DVDs are capable of storing up to 17GB of data.
The data transfer rate of DVD drives is comparable to that of hard disk drives.
DVD-R and DVD-RW drives have the ability to read/write data.
Solid State Storage Devices
Solid state storage devices use nonvolatile memory chips to retain data.
They do not have moving parts.
They are small, lightweight, reliable, and portable.
Examples of Solid State Storage Devices
Figure 1 b: Solid State Storage Devices
Compact Flash Memory
UNIT 2: The windows environment
Before you work with different computer applications you need to be familiar with the windows environment. It is this environment that you will be using in performing different tasks with your computer. For simplicity and standardisation, this module shall use windows 7 operating system environment as well as Microsoft Office 2007 applications. Please note that this work is not to promote a certain software producer but to impart knowledge and skills to students. After going through explanations and examples in this module, the student is advised to try exploring the same concepts in different hardware and software environments.
The windows aspects that you shall learn in this section include the desktop, the general office window and its sections, folder management and basic windows tools.
Figure 2b: The windows desktop
Figure 2b shows how the desktop looks like. Note that the background differs according to the individual user preferences, so expect to see different desktop backgrounds whenever you encounter a different desktop. The desktop is what you see when the computer has finished booting up. It is equivalent to the top of your desk when are working in your office. You may remember that on your desk there are all tools that you need to do your daily tasks. On one’s desk we would expect to see pens, rulers, calculators, diaries, trays and so on. On the sides of the desk you may have a dust bin to throw unwanted papers.
The emergence of the electronic office resulted in converting all those functions into electronic form. We now have pens, rulers, recycle bin and other tools that we need to use in our electronic office that makes minimum or no use of papers. Next we are going to explore the different tools that we have on our desktop.
Standard desktop icons
User created folders
On standard widows desktop there are icons which are there and are expected to be there. On figure there are two standard desktop icons namely Computer and Recycle bin. As a user you can also create your own folders on the desktop in which you save your work. In figure we have two folders named, All others and ITCA work. A user can create as many desktop icons as required. However, it is advisable to have very few icons on your desktop so as to avoid cluttering it. You need to plan how your work needs to be organised carefully. You may need to have as few as five main folders on your desktop possibly corresponding to all the modules you are doing that semester. If you are doing communication, introduction to computers, Statistics, Entrepreneurship and Life skills; you may need to create a folder for each of the five. Then in each folder you can create more folders e.g. tutorials, lecture notes, self notes, exercises and assignments. The subfolders may also be subdivided into sub-sub folders. If you practice this you will notice that it will be a lot easier for you to locate anything of interest.
One can also save documents on the desktop be it word, spreadsheet, database, presentation etc. On figure the word document Automatic gate system was saved on the desktop. Note that it is not good computing practice to save documents directly on the desktop.
The desktop can also carry certain icons that are often used for example in figure there is Google chrome and Skype. Some software when installed on your computer will automatically put a desktop icon for easy access to it.
At the bottom of Windows 7 desktop window there is a series of icons corresponding to major applications running on the computer as well as active program icons. Figure shows such icons.
Basic operations in the Windows environment
Before you proceed to the next sections of this module, you have to acquaint yourself with the following basic operations:
Opening a document
Saving a document
Backing up a file
Print previewing a document.
Word processing involves creating textual documents using your computer as well as saving and printing those documents. The documents may be letters, memos, reports, assignments, etc. In your studies you will be required to write many of such documents. It is therefore critical that you are competent in word processing. The skills you will acquire in this area will be useful in writing your assignments and projects in your programme, at home and at work.
This module will not cover everything in word processing but limited to the structure of word processing window and a few word processing activities enough for building a base for your work.
The word processing window
Figure shows the main elements of the word processing window.
The grey area at the center of the window is called the work space or working area. You type all your work in this area. Let us explore the various parts of this window in the following sections.
Main menu bar
Minimise, maximise and close
The office button
The office button is found on the top left corner of the window. Clicking on the office button will produce the drop down menu as shown in figure below:
The drop down menu is comprised of new, open, save, save as, print, prepare, send, publish and close. These are the standard actions that you can perform while working on your documents. In your practical session you will familiarise with all these actions. You use the new action when you intend to create a new document e.g. a memo or a letter. The open action is used to open an existing document that has been saved either in the computer hard disk or any external storage device e.g. a memory card or memory stick.
The office button can also help you access any recently opened documents without bothering you with remembering where you saved the document. In this case the recent documents are listed thus ITCA module, Farai CV Telecel etc.
The tool bar contains standard tools that you can use to do several things while working with your document e.g. copying, pasting, indenting changing font colour and so on.
As the name implies this is the position where the name or title of the document name is located. Once you save your document the name that you give to the document is the once that is written in this bar. Figure shows that the document I was working on is called ITCA Module which is a Microsoft word document.
Main Menu bar
The main menu contains several menu items that are used in working with your documents. Every action starts here. These are called main menu items because once you click on each of them a different set of sub items are displayed allowing you to perform certain specific actions. Figure shows the main menu and its menu items.
The main menu items are the Home, Insert, Page layout, references, mailings, Review and View. Each of these menu items has several submenus corresponding to it. If you click on any of these items a different set of submenus will be displayed. Figure and figure show the submenus of Home and Insert respectively. You shall learn the use of each of the items in the submenus in your practical sessions.
The submenus of Home are Clipboard, Font, Paragraphs, styles and Editing.
The insert menu option has the submenus Pages, Tables, Illustrations, Links, Header and footer, Text and symbols. Each of these submenus has a set of tools that you shall use to perform small tasks in when working with your documents.
UNIT 3 Role of ICT in Business
Information and communications technology (ICT) is often used as an extended synonym for information technology(IT), but is a more specific term that stresses the role of unified communications and the telecommunications (telephone lines and wireless signals), computers as well as necessary enterprise software, storage, and audio-visual systems, which enable users to access, store, transmit, and manipulate information.
Information Communication Technology (ICT) is a generic name used to describe a range of technologies for gathering, storing, retrieving, processing, analysing, and transmitting information.
ICT in Business
ICT in a business environment can be used for:
Manipulating data and
ICT is used in
Administration- For Invoicing, Communication, Emailing.
Business, Finance and Accounting- for Business Plans, Financial forecasting, Auditing, Market Analysis, Research, Recording Transactions.
Communications- For email, instant messages, mobile phones.
Engineering and Creative Art- for 2D and 3D Drawing, Modelling, Simulation.
Wildlife and Tourism and Hospitality- Animal Tracking, Hotel booking, GIS.
Characteristics of today’s business environment
Today’s business is very different from the traditional business environment. Figure shows the four main aspects that characterise the modern day business environment. These aspects are the nature of business, technology, customers and the market.
The nature of business
Three Spheres of Web Strategy
When we talk of the web strategy we refer to how a business would deal with the issues that affect the way they appear to the outside world through their websites. Nowadays people know about an organisation mainly through visiting their website on the Internet. So, the business managers need to constantly update their information on these websites. The nature of your website and its content determine largely how your business will fare.
A good website should balance the three elements shown in figure 3a (community, technology and business)
Consider a website that focuses only on the community and the business. In this case the website takes into account the expectations of the community first and fuse them into their website. You realise that every business operates in a certain environment and serves a specific community. It is paramount to note that each community has its own norms and values that shape its people’s expectations from the business. So a wise business manager has to make a thorough investigation into these norms, values and expectations. On the other hand the business has to be understood in terms of its processes and procedures.
The website now has to reflect the community expectations and the business processes and procedures. As figure 3a shows, this type of website will be inefficient for the success of the business. The website needs to be hosted on the Internet hence technology tools are required.
A business that ignores the community and focuses on the business processes, operations and expectations taking into consideration the modern IT technology is likely to fail again. As indicated in figure 3a users will be frustrated and may not even come onto the website. In this case the business will eventually collapse. Clearly no business can survive when it does not recognise the norms, values and expectations of the community that it serves. So make sure that pictures, logos, icons and everything that you use on your business is in line with the community if you want your products to do well. Imagine someone with a UK background where an owl is considered a lucky bird comes to Zimbabwe and puts pictures of an owl on every page of the website as well as banners to advertise the products!!!!!!!!!!!!!!!!!!!!!!!!!!! Pakaipa pakaipa. People will run away. The reason is simply that an owl in Zimbabwe is associated with witchcraft. So take the people’s culture seriously when branding your products.
Another approach may be taking only the society and the technology seriously. Clearly this does not work because the business functions and processes themselves are left out which should be the main reason of existence. Only a fool will ignore the business since the result is monetisation issues where no transitioning will occur. Actually there will be no business to talk about.
Finally, the proper way of doing it is considering the community, the business and the technology equally and inculcates them into the website development and maintenance always. When this is adequately done we now talk of web strategy balance. This is the optimal way of running a business properly online.
Internet, Email and E-Commerce
The Internet connected every part of the globe. The globalisation of business resulted in us having the following
Global Market Place
Price Comparison Sites
Messages can be sent to individuals and groups
Quick Information Transfer
Electronic commerce came also as a result of doing business on the Internet. The benefits that accrued to business following this include the following;
Speed- Quicker processing times save the business time and money. Transactions are processed on quicker on real-time
Accuracy- with the use of verification and validation, data can be inputted more accurately. This can help with decision making.
Data Handling- Can be inputted and manipulated anywhere on the market
User friendly- Easy to use
Capacity- Large quantity of data can be held with very little physical space
A computer network is a group of computers connected to each other electronically.
This means that the computers can "talk" to each other and that every computer in the network can send information to the others.
The components of a computer network include: a computer, the router, the gateway, the bridge networking device, the switch for networking and the hub. Most of these are data terminal equipment and components of networking that are tasked with receiving or generating data.
A virtual private Network (VPN) extends a private network across a public network, such as the Internet.
Definition of terms
A database is an organized collection of data.
A computer is a general purpose device that can be programmed to carry out a set of arithmetic or logical operations
A router is a device that forwards data packets between computer networks, creating an overlay internetwork.
A network switch (sometimes known as a switching hub) is a computer networking device that is used to connect devices together on a computer network.
It is the transformation of an organization’s processes to deliver additional customer value through the application of technologies, philosophies and computing paradigm of the new economy
Three primary processes are enhanced in e-business:
Production processes, which include procurement, ordering and replenishment of stocks; processing of payments; electronic links with suppliers; and production control processes, among others;
Customer-focused processes, which include promotional and marketing efforts, selling over the Internet, processing of customers’ purchase orders and payments, and customer support, among others; and
Internal management processes, which include employee services, training, internal information-sharing, video-conferencing, and recruiting.
Software are the instructions given to a computer in the form of a program.
Software is the set of programs, which are used for different purposes.
Software are all the programs used in a computer to perform certain tasks.
Categories of Computer Software
Types of Software
Software is divided into two broad categories:
Systems software and
Systems software is the term used to describe programs that enable the computer to function, improve its performance and access the functionality of the hardware.
Function of systems software is the control of the operation of the computer.
Systems software provides the foundation for applications software.
Operating System Software
Systems software is further subdivided into operating systems and utilities.
The operating system is the program that actually makes the computer operate.
Examples: Windows 7, 8, Linux
Operating System Software
It is the basic minimum software needed for a computer to be functional.
It constitutes the greater part of Systems software.
Its major function is to control the hardware
Functions of an Operating System
Functions of an Operating System
Boot-up the computer.
• Control the hard drives: This includes such features as formatting and defragmenting disks as well as saving files to and retrieving files from disk.
• Control input devices such as keyboards, mice and scanners.
• Control output devices such as the video display and printer.
Control the external ports: Ports are the external connections that enable peripheral devices to be connected to a computer. Common types of ports are serial, parallel, USB. Of these the USB ports are the most important.
• Provide the functionality for computers to be linked in a network.
• Provide the foundation for application software to be launched.
• Enable application software to access and use the hardware.
Utilities Software are programs which either improve the functioning of the operating system or supply missing or additional functionality.
Examples: Windows Explorer (File/Folder Management), Windows Media Player,, WinZip, WinRAR for compressing files
Application software is used in real-world tasks to solve user problems
Application software is used in real-world tasks to solve user problems
Types of applications software
Off the shelf
General applications that can be purchased from vendors. E.g. Microsoft Office
2) Custom software
Software specially designed for a particular industry or organization E.g. Galileo/Worldspan (Travelling Agents) , ASCUDA for ZIMRA border clearance, POSware for supermarkets etc
Versions of software
The new releases of software products are called versions.
The versions use a numbering system such as
Windows 7, Windows 8, MS Office 2010.
Why …. Versions of software
Software developers continually strive to improve the performance of their products and add new features.
Especially in a world of competing products, each developer needs to make their product perform better, have fewer problems and have more features.
Relationship btwn s/w, h/w and users
Basically in two forms i.e.
Open source software
Also called non-free software, is software with restrictions on using, copying and modifying as enforced by the proprietor(owner).
Restrictions on use, modification and copying is achieved by either legal or technical means and sometimes both.
Examples of proprietary software are Microsoft Windows, Microsoft Office, Norton Antivirus etc.,
Open Source Software:
Open source software (OSS) is computer software whose source code is available under a license that permits users to use, change, and improve the software, and to redistribute it in modified or unmodified form.
It is often developed in a public, collaborative manner.
Common OSS products are Linux, Netscape, Apache, etc.,
It is copyrighted software given away for free by the author.
You are unable to view the source code
Although it is available for free, the author retains the copyright, which means one cannot do anything with it that is not expressly allowed by the author.
Usually, the author allows people to use the software, but not sell it.
Examples: Adobe PDF, Google Talk, Yahoo Messenger
Freely distributed for a trial period
You can only enjoy a free trial of it for a short period e.g. 14 days after which you are required to pay for a license
The author usually requests that you pay a small fee if you want to use the program regularly.
By so doing, you become registered with the producer so that you can receive service assistance and updates.
You can copy shareware and pass it along to friends and colleagues, but they too are expected to pay a fee if they use the product.
Shareware is inexpensive because it is usually produced by a single programmer and is offered directly to customers.
Thus, there are practically no packaging or advertising expenses.
Note that shareware differs from public-domain software in that shareware is copyrighted.
This means that you cannot sell a shareware product as your own.
Failure of any program (such as a word processor) to install correctly from its distribution disks.
Programs which are NOT viruses:
Trojan horse: a standalone program which does its damage immediately, while you are running it for another purpose (usually a game!).
Bomb: a standalone program (like a Trojan horse) whose only effect is to destroy some part of your system (programs, data) but does not pretend to be another program while it runs.
Bug: a legitimate program with some logic error which causes accidental damage to your system even though everything was done according to the manual.
User error: a human error (which the human may deny!) which causes loss of data or programs, or damage to hardware, due to accident or entry of incorrect commands.
Formats hard drive, destroying all data ("Dark Avenger").
Causes random change in typed characters ("Teatime" virus).
Presents a political or (false) advertising message every few times ("Stoned" virus: Legalize Marijuana).
Causes computer to act as though a monitor or disk drive is going bad ("Jerusalem-B" virus).
Where viruses can hide:
In the "boot" sector of any floppy disk. This is a small program which runs whenever the computer is "booted" from the diskette, whether or not the diskette is "bootable." (This is the tiny program which puts the message "Non-system disk or disk error" on the screen if the disk is not bootable!)
Attached to any program: shareware, commercial or public domain.
Embedded in the hidden system files IO.SYS and MSDOS.SYS on the boot disk or drive.
Same as #2, but pay SPECIAL ATTENTION to the file COMMAND.COM on the boot disk or drive.
The "partition table" on a hard drive. (This DOES contain executable information, since it is attached to the "Master Boot Record" which is consulted at boot-up to determine whether to boot DOS, OS/2, UNIX, etc.)
How viruses are spread:
Trading, copying or pirating software on diskettes without knowing the source.
Software salesmen giving demos on your computer from their diskettes.
Computer repair personnel using diagnostic disks.
Computer user groups and bulletin boards (BBS's). NOTE: #2 & #3 account for over 80% of all infections at business sites! #1 accounts for nearly all others, #4 LESS THAN 5%.
When viruses activate:
Every few times the computer is booted up
On a certain day of the year
On a certain day of the week ("Sunday" virus).
On a certain day of the month ("Friday the 13th", "Saturday the 14th" viruses).
Every day EXCEPT one ("Israeli" or "Suriv03" virus, every day except Friday the 13th.)
On a certain date only. (Jan. 1, 2000 "Century" will activate, write zeroes to all connected disks, effectively destroying all data and programs, destroying all directories, file allocation tables, boot records and partition tables, possibly causing the disk to have to be returned to the dealer for repair. Finally, a message is presented to the user, "Welcome to the 21st Century.")
A certain period after infection ("Plastique" virus, one week).
After infecting a certain number of files ("MIX/1" virus, six files).
After a certain number of keystrokes ("Devil's Dance" virus, 2000 keystrokes; after 5000 destroys hard disk data and prints characteristic "Devil's Dance" message).
At a particular time of day ("Teatime" virus, between 3:10 and 3:13 PM, trashes every 11th keystroke.)
Any combination of the above, plus anything you can probably think of!
Types of viruses, classified by how they spread ("vectors"):
Boot-sector viruses. Can NOT be transmitted from BBS's at all. Transmitted by floppy or tape cartridge (rare). Boot- up must be attempted from infected disk. Remains memory- resident during warm boot, infects boot sector of all other disks in system including hard and floppy disks.
Program viruses. May be transmitted by distribution of infected programs via floppy, BBS or network. Some infect ONLY COMMAND.COM; others avoid infecting COMMAND.COM, to avoid detection.
Types of viruses, classified by operating system:
DOS. Greatest variety of viruses due to widespread use.
Amiga-DOS. Restricted to Commodore Amiga.
Macintosh. Restricted to Macintosh computers. NOTE: Amiga(TM) and Macintosh(TM) computers often have a DOS emulation mode. In this mode, some (but not all) DOS viruses can damage them as well.
OS/2. Relatively immune to viruses so far, due to rarity of systems. Most DOS viruses are rendered harmless by OS/2, although some may still survive since OS/2 can also run DOS programs.
UNIX. These viruses are relatively rare, but some have the potential of migrating to PC's running UNIX clones such as XENIX. Similar remarks apply to Amigas and Macintoshes running A/UX or other UNIX clones.
VMS, MVS, etc. (Minicomputers & mainframes). A few viruses spread over networks. More commonly affected by worms (RTM Internet worm, e.g.), logic bombs via e-mail, etc.
Conditions for propagation  (epidemiology):
Many computers in close proximity. "Proximity" may not be physical distance between computers, but between computer owners in the same class or job.
Frequent exchange of susceptible software.
Long incubation period of virus.
Proportionately few "immune" individuals in the community, i.e. those using anti-viral software.
Use of software brought from home, where "the kids" could bring home viruses from school, etc.
Prevention of virus infections or attenuation of epidemics:
Remove any of the conditions above.
Isolate computers. This is seldom practical! But you can set aside one computer in an organization on which to try out disks and software before releasing disks for general use.
Don't be hasty to try every new program that comes down the pike.
Use the computer set aside in #1 to set future dates and see if anything happens.
Use anti-viral software on ALL computers, and keep it updated regularly. (The few users who don't use the software will be protected by "herd immunity" which is well known in disease control.)
Disallow use of any software not purchased by and for the corporation, or disinfected as in #1 and #3.
UNIT 6: Computer Generations
The development of electronic computers can be divided into five generations depending upon the technologies used. A computer generation is born when there is a departure in technology.