introduction to information technology
hcs 115
P.S. MUPFIGA
Introduction...... 5
USES OF INFORMATION TECHNOLOGY...... 6
Computer Hardware and software...... 8
Input...... 8
Processing and Control...... 9
Output...... 9
Storage ...... 10
Cache memory...... 11
The Central processing Unit...... 12
Main memory...... 12
The Arithmetic Logic Unit...... 13
The Control Unit...... 13
SOFTWARE...... 13
System Software ...... 13
Application software...... 15
Factors to consider before buying a software...... 17
Data Processing...... 18
Types of processing...... 19
Types of computer systems...... 21
Databases ...... 21
Resource Database...... 22
EMPLOYEES...... 22
PAYROLL...... 22
BENEFITS...... 22
Advantages of Databases...... 23
Computer Networks and The Internet...... 24
Definition of terms...... 24
Reasons for networking computers...... 24
Local Area Networks and Wide Area Networks...... 25
Network Topologies...... 26
Ring Network...... 26
Star network...... 27
Bus network...... 28
The Internet...... 28
Information browsing...... 28
Electronic mail (e-mail)...... 29
Newsgroups...... 30
File transfer Protocol...... 30
Requirements for one to connect to the Internet...... 30
USES OF THE INTERNET...... 31
WORD-PROCESSORS and SPREADSHEETS...32
Word-processing...... 32
Spreadsheets...... 34
3. COUNTIF...... 37
Drawing Charts and graphs from given data...... 37
INFORMATION SYSTEMS...... 39
Information Systems In Business...... 39
Marketing Information Systems....... 39
Manufacturing Information systems...... 40
Accounting Information Systems....... 40
Financial Information Systems...... 40
Security and Ethical challenges in Information Technology 41
Security in Information Systems...... 41
Administrative controls...... 42
Input Controls...... 42
Storage controls...... 42
Physical protection...... 43
Disaster recovery plans...... 43
Ethical Challenges of Information Technology...... 43
Viruses...... 43
Societal Implications of Information Technology...... 44
Past Exam Papers...... 45
Introduction
Information technology refers to hardware, software, databases, telecommunication technologies and other information processing technologies that manipulate data resources into useful information products like reports, financial statements. Consider the example of a person who goes into a banking hall to inquire his balance. That technology they would use to create, store, manipulate and communicate information is what is referred to as INFORMATION TECHNOLOGY.
Closely related to information technology is an Information system, which refers to the set totality of requirements for handling information within an organization. It can also be considered as an organized combination of people, hardware, software, communication networks and data resource that collects, transforms and disseminates information in an organization. An information system can be manual (i.e. paper work) or informal (word of mouth), however the aspect of the module is specifically computer based information systems that use information technology.
These are some of the common terms in Information Technology:
Hardware – the name given to all physical components of a computer system. These are mechanical, optical, electronic or magnetic devices or components of a computer or generally the physical makeup of a computer
Software are the various non-tangible computer programs, procedures and their associated documentation concerned with the operation of an information system. Example Microsoft Word is software for typing. The are software for games, for accounting and many other disciplines.
Data – are raw facts, figures or observation about a transaction or physical phenomena. E.g. Sam, 12, St Johns. Hence data objective measure of attributes, of entities.
Information - is processed data that is put into a meaningful context for the intended recipient e.g. a report, receipt. We feed data into an information system and it provides information.
A program is a set of instructions written in the language of a computer. When a person is using a computer, say when playing chess with a computer, the computer will only be responding to programmed instructions that assist it in making the most appropriate move.
Enduser – any one who uses an information system or its products. Consider the person who designed a computer game; the enduser would be anyone who then plays the game. In an Accounting Information System endusers include people like data capture clerks, bookkeepers, and even managers who would need financial statements.
USES OF INFORMATION TECHNOLOGY
However inexhaustive, the applications are tailor-made to increase effectiveness at work, increase customer satisfaction, make work easier, and increase productivity, to communicate and in general think of every sector of the country’s economy and imagine the magnitude of contribution provided by Information Technology.
Information Technology comes as:
A major source of information and support needed to promote effective decision making by managers.
An important ingredient in developing competitive products and services that give an organization a competitive advantage on a large scale.
A functional area of a business in accounting, recordkeeping, human resource management, marketing, research etc. Consider the example of banks that use information technology to store information about the account holders and their various banking transaction requirements accurately, conveniently and safely.
A vital, dynamic and challenging career opportunity for millions of men and women.
A substitute or a compliment for human effort and in the end automating production, or business processes.
A tool to gain competitive advantage. Most of the companies that store data or process transactions using information technology are generally favoured by the widest web of clientele since they provide security of data, convenience to customers, and tend to be faster.
Information Technology has become a vital component of successful businesses and organization in terms of data processing, communication, office management, commerce e.g. banking, data security and report generation.
IT guarantees security of confidential information through passwords, accuracy of reports (which are not subjective and biased) and faster retrieval of information.
Examples
- One can apply for a job, college placement or make quotations and orders via email and the mail will reach the recipient instantly
- Student can research on a wide range of topics by accessing information in websites across the world.
- IT is also used to market organizations and their services
- Managers use computer systems that are able to integrate various functions of an organization and then assist managers in decision-making and trend forecasting.
In the end, Information Technology increases an organization’s competitive advantage, increases revenue, reduces costs, improves quality and creates new opportunities.
Assignment
Why has your institution invested a lot in information technology? [answer should be in clear point form]
Computer Hardware and software
A computer is basically responsible for carrying out the tasks of accepting input, storing, and processing, controlling and producing output. In deed a computer exists as a system not a unit with input, processing, storage and output being the subsystems. These subsystems are not complete in their own right, in the sense that they are thinly connected through software.
Input.
Is a means of entering data into the computer through input devices such as keyboards, joystick, touch screen, mouse, bar code readers etc. Computers can not accept data in forms customary to human communication hence input device convert/ or present data to the computer in a machine readable electronic or digital form (using a series of 1s and 0s to represent numbers, letters and even voice and pictures). Hence the input unit is an interface between the user and the computer. Input devices are often called peripheral devices
Other common forms of input are:
a)Optical character recognition translates code or marks on source documents into digital forms that are understandable by the computer. OCR is used mostly in some supermarkets which have a hand held reader that scans a commodity’s barcode and can then be able to deduce that type of commodity and its price.
b)Light pen, uses photoelectric circuitry to enter data through the video screen
c)Pointing devices are among others – mouse and touch screens. The mouse uses point and click options to select and run commands on Graphical User Interface screens. Moving a mouse corresponds to the movement of the mouse pointer on the screen and clicking an icon runs the program that is represented by that icon. Using a touch screen a user point on a sensitized monitor to select commands or options other than pressing buttons on a keyboard.
d)Other input devices include scanners for reading pictures and sensors for reading analogue data like temperature
Processing and Control
A computer’s control unit is responsible for fetching instructions from main storage, interprets them ant then issues necessary signals to components making up the computer system ordering them to perform required operations (fetch and execute cyc4les)
The Arithmetic Logic Unit of a computer is responsible for making calculations required in computer processing. It makes comparison on data (logical calculations like >, <, >= etc) at very high speeds as part of processing. The Arithmetic and Logic Unit Combined with the Control Unit forms the processor.
Output
Data is processed to produce output. Computer output can be sent to a printer, seen on the screen or stored in storage device. In most information systems output comes in the form of printed or onscreen reports or audio etc. Examples of output devices are printer, speakers and the monitor.
Video display is the most common type of computer output. Broadly these are displayed on either monochrome (black and white) or color monitors. These differ in their resolution, which is a measure of their clarity (in terms of smoothness of the pictures), an expression of the number of pixels per inch.
Printers produce what is commonly referred to as a hardcopy (print out).Printers can be:
a)Character printers, which imitate the operations of a typewriter by printing one character at a time by hitting a ribbon on top of a paper, thus they are often referred to as impact printers. These printers are slower.
b)Line printers print one line at a time and are faster than page printers. These can print pictures and examples are inkjet printers.
c)Page printers are heavy duty fast printers which are exploited for commercial purposes and the include laser printers. They produce high quality printouts.
Output can also be in the form of voice or audio through speakers.
Storage
A computer has the capability to store data that it is currently using, that will be referred to at a latter time (semi permanent) or that starts a computer. Storage is divided into 2 namely:
Secondary / Backing Storage – stores information on devices like CDs, diskettes, Hard disk and tapes. When one saves his essay, letter or project, he would have stored it in any one such device such that he can refer to it any time he prefers.
HARD DISKS
One or more hard disks are found in the hard drive which is usually housed inside a computer. Each drive is built into a sealed unit to prevent contamination by dust and moisture. A hard disk pack consist of several platters with data encoded on both sides of the platters (except for the top platter’s top part and the bottom platter’s lower part.) accessed by the read/write heads.Advantages over floppy disks :
- Access to data is faster than from floppy disks.
- Hard discs store more data than floppy disks. (40 Gb drives are now common).
- They are more reliable than floppy disks as they have more protection from dirt.
One disadvantage of a hard disc over floppy disk is that it is not portable - you cannot carry it round and use it on different computers. / The read-write head floats so close to the disk that a small speck of dust would ruin the disk. This is why the drives are sealed.
FLOPPY DISKS
Are flat, rotating, 3.5” polyester film disks covered with a magnetic coating on which data is recorded. Most common floppy disks have a capacity of 1.44Megabytes. As with hard disks, data is stored on tracks and sector and they use direct access to locate and read a certain block of data.
Main storage stores the bootstrap loader (i.e. those programs that start running when a computer is switched on) and active documents or programs (i.e. a running program or open document). It also stores the operating system programs that manage the operation of a computer and the data that is being used by the programs. The following are types of main storage
Random Access Memory (RAM), which holds instructions and data between processing, stages and supplies them to the ALU and CU during processing. RAM looses its contents if power is switched of i.e. it is volatile. RAM stores data and instructions requiring processing, being processed and awaiting output hence the name working area of the computer.
Read Only Memory (ROM) stores programs that start running when a computer is switched on and holds character patterns. ROM stores permanently and its contents are set permanently during manufacture. We have the ROM inside the circuit board below. ROM forms part of hardware, hence the name firmware.
Cache memory
Cache memory is a high speed memory mainly used to complement the RAM. Cache memory is faster than RAM and it stores frequently used pages. The cache memory is between the RAM and the CPU and the CPU searches for data or programs in the cache first, if its not found, the CPU then searches in the RAM. The CPU uses certain algorithms to determine which data should be stored in the cache, which will help the CPU to predict the next instruction to be executed and hence making processing faster.
Logical Structure of a computer
Input Devices e.g.
Keyboard, mouse,
Scanner, audio
e.g. printer, monitor
The Central processing Unit
As depicted by the diagram above, the Central Processing Unit is made up of the Control Unit, the Arithmetic Logic unit and the main memory. It is the unit that controls the interpretation, storage and execution of program instructions. It contains most of the circuitry of the machine.
Main memory
Main memory is a high-speed storage unit that determines (to some extent) the speed of a computer. It includes registers (which store one unit of data) for high-speed temporary data storage.
The Arithmetic Logic Unit
The ALU handles all the calculations that must be done as a way of processing. Consider the example of a computer calculating an employee’s salary on the basis that if he works up to 40 hrs he will be paid at the normal rate otherwise he is paid at the overtime rate. The ALU will make a logic calculation to determine if the hours worked are greater than 40 and go on to carry out the appropriate arithmetic calculation depending on the results of logic comparisons. Basically the ALU carries out calculations of addition, subtraction, division, multiplication etc and logic calculations of >, <, <=, = which will direct the control unit to operate or issue a certain instruction to the other parts of a computer. The logic operations give a computer some decision-making capability. It should be noted that the data processed by the ALU comes from the main storage as directed by the control unit and stored in the ALU’s registers.
The Control Unit
The control Unit manages the CPU by initiating instruction fetch and execute
It control and co-ordinates the operation of all hardware operation and allocates them duties. It fetches instructions from the main memory interprets them and then issues instructions to respective parts of the computer system to perform the required operations. It enables the whole computer system to work as one unit.
SOFTWARE
Software refers to various programs and their associated documentation that bring life into computer hardware by directing its use. Software can be subdivided into system software and application software
System Software
System Software is usually supplied by the manufacturer of a given computer component. When one buys a printer it comes with CD software that enables it to work with other system components of a computer. System software contributes to control and performance of a computer system. System software acts behind the scenes to manage resources and operations of a computer system. System software interfaces between computer hardware and the application software.
An operating system is software which controls the general operation of a computer.An operating system
- controls the loading and running of programs
- controls the use of peripherals such as disc drives and printers
- organises the use of the computer’s memory.
- handles interrupts (signals from devices)
- maintains security (passwords etc)
A computer cannot work without an operating system.
Examples of Operating Systems :
- UNIX
- Linux
- Windows
- MS-DOS
The greatest part of system software is the operating system (e.g. Windows) which is responsible for user interface (i.e. the ease of communication with the computer user), resource management (i.e. ensuring proper sharing of memory, proper use of the printer etc), file management (that controls, the creation, opening and deleting of files) and task management in such a way that such programs allow sharing of processor time and to allow for the running of many computing tasks at the same time.
The user interface is the way the user interacts with the computer.The three main types are :
Command / The user types in commands.
Programs use less memory.
Example : The MS-DOS interface.
Type DIR /W to get a list of all the files in a directory.
Quick to operate and very flexible, but the user needs to learn all the commands and type them in correctly.
Menu / Drop-down menus have options for selection. There may be sub-menus...
The user selects an option with either a key or a click of the mouse.
No need to learn the commands but it can be difficult to locate a particular option.
GUI / Graphical User Interface
Also known as a WIMP (Windows, Icons, Menus, Pointers) interface.
Icons (small pictures) represent options. Colour and sound may also be used to make the interface more 'user-friendly'.
Identical icons may be used in a number of different programs. Eg a picture of a disk to save a file.
Example : Windows
Low-level IT skills needed by the user. Easy to use intuitive interface.
Sound / Speech driven interfaces are also now available. The user talks a command into a microphone.
Useful for...handicapped, fighter pilots, surgeons..
/
Detail of a GUI interface
Application software
Are programs that carry out specific tasks for the computer user for example Microsoft Access is for databases, Microsoft Word is for Typing or Word-processing while Microsoft Excel is for Spreadsheets