Basics Of Information Technology and Computer Science: We are income in the information age of a global village today. That way information is the key factor in this era plus it is rightly said that “information is the most precious product of today’s day-to-day business”. all evolves around it whether it is education, medicine, history, ecological phenomena, sports, research or business. You name the system plus information is there to play a key role in its functionality and continuation.
Information can be defined as the facts and figures about anything i.e. the know-how about any object that exists and plays its role in any system. The system is any identified and known work that accepts data / information into itself, manipulates in the shape of certain output(s) and delivers so that it becomes useful and meaningful. And precisely, that is what is known as “Data processing” or “computing”, for which we need a computer to accomplish the task.
Few years back, this accomplished task was available to the computer users/clients in a prescribed locality only. That locality could be his own office or organization. But with the advent of communication technology, our globe has become virtually a one-community area i.e. global village. The organizations expanded to remote cities and countries and it was felt to make the data/information and the ultimate accomplished task available to them where-ever they are. There came communication technology to our rescue and a new term emerged i.e. “information technology” that can be precisely defined as:
“information technology is the technology that merges computing with high-speed communication links carrying data in the form of text, sound, images, video etc”, from place to place over this global village. For this purpose, the computer systems are networked in such a way that the data/information stored/processed on them is always available from anywhere, at any place, at any moment.
Thus, the computer users are almost always sharing and exchanging their information in such a manner as if they are sitting in a drawing room face to face. So in short, information technology enables the heterogeneous types of industries and institutions to a phenomenon known as digital convergence. The digital convergence is the technological merger of various industries/ enterprises through some electronic gadgets that exchange information between them.
The industries are computers, electronics, telecommunications, and mass media etc. it has tremendous significance in modern scenario. It means that from a common electronic base, information can be communicated to any shape that the users are accustomed to see i.e. photographs, movies, audio, graphical shapes, text form, analog diagrams etc.
Modern Scenario Of Computer Science
Modern Scenario Of Computer Science: The fresh impact of information technology has broadened the base of computing plus communication through satellite, fiber-optic, mobile phone, fax machine, multi-media/hyper-media, e-commerce, m-commerce etc. etc. thus enhancing the insinuations of this shift from single, cut off technologies to a unified digital convergence and enabling the computer users to knowledge a beautiful and fantastic scenario of computer utilization in the fields like:
(i) Artificial intelligence
(ii) Web-based Applications
(iii) E-commerce, M-commerce (Mobile Commerce)
(iv) Computer animation
(v) Multi-media, Hyper-media
(vi) Distributed computing
There are numerous fields of computer applications, but we need not to go into the details of all those as it is beyond the scope of this lesson. What we need to know here is that the information technology has brought about a revolution in our life style. We may call it the computer Revolution, information Revolution, communications Revolution, internet Revolution, multi-media revolution or whatsoever. So it is beyond any doubt that today, we are living in a society that is making use of “Information Highway” which is heading towards a real future “ global village” of the human history.
Hardware and Software
“A computer is a device that can be programmed t accept data (input), process it into helpful information (output), and store it absent (in a secondary storage device) for safekeeping or later reuse”. We have four words in this meaning which are of prime importance in the whole computing process i.e. machine, programs, input and output. By conventions, machine is called hardware, whereas a program is known as software in the discussion of computer science. Here, input and output devices are part of the machine that can now be called as a complete computer system. So, to function, a computer system requires four main aspects of data handling i.e. input, processing, output and storage (figure 1.1). the hardware, responsible for these four areas, operates as described below:
- Input devices accept data in a form that the computer can use, and then sends it to the processing unit.
- The processor (CPU), has the electronic circuitry that manipulates input data into the form of useful information. The processor actually executes the instructions (Programs) in a logical sequence.
- Output devices show us the processed data i.e. information, in the shape we want it.
- Storage usually means secondary storage, which consists of secondary storage devices, such as hard disk, floppy diskettes, CDs et. Which can store data and programs outside the computer itself. These devices actually supplement main memory, which can hold data and programs only temporarily.
Figure 1.1:A generalized computing environment
According to the definition given in the section 1.2 above. We need some device(s) to enter the data into the computer (input devices) and some device(s) to see the outcome (or processed information) of the computer (output devices). Both are discussed as below:
Input devices
Sometimes, the data is entered directly to the computer and sometimes indirectly. In the first case, the data goes directlyto the computer from the source and in the second case; we have to carry out some intermediate handling. In either case the task is to gather data to be processed by the computer. There are three general types of input hardware, namely:
- Keyboards
- Pointing devices
- Source data-entry devices
Keyboard: the keyboard may look like a typewriter keypad to which some special keys have been added. The keys normally available on the keyboards are numeric, alphabetic, function and additional special-purpose keys. Figure 1.2 shows the complete layout of an extended keyboard on a personal computer. It has some additional keys between the main keypad and the numeric keys, and status lights in the upper-right corner. This standard keyboard is also called “QWERTY”, which describes the beginning keys in the top row of alphabetic letters.
Function keys: the function keys are an easy way to give certain commands to the computer. The particular software we use defines what each function key does.
Main keyboard: the main keyboard includes the familiar keys found on a typewriter keypad, as well as some special command keys. The command keys have different uses/effects that depend on the software being used. Some of the most common uses are listed here:
101 –Key “Enhanced” Keyboard Layout extra buttons and keys are based on this layout.
Figure 1.2:A 101 –key “Enhanced” keyboard, showing the layout of the various key groups.
The Escape key, is used in different ways by different programs; often It allows to “escape” to the previous screen of the program.
The Tab key, is used to tab across the screen and set tab stops as on a typewriter.
When the CapsLock key is pressed, upper case letters are produced. Numbers and symbols are not affected. The number or symbol shown on the bottom of a key is still produced. When the CapsLock is pressed, the status light under “CapsLock” lights up.
The Shift key is pressed in combination with other keys to produce upper case letters and the upper symbols shown on the keys.
the Control key is pressed in combination with other keys to initiate commands as specified by the software.
The Alternate key is also used in combination with other keys to initiate commands.
the Backspace is used to delete a character to the left of the cursor, moving the cursor back one position. The cursor is the flashing indicator on the screen that shows where the next character will be inserted.
The Enter key moves the cursor to the beginning of the next line. For instance it is used at the end of a paragraph.
Numeric keys
The numeric keys serve one of the two purposes, depending on the status of the num lock key. When the computer is in the num lock mode, these keys can be sued to enter numeric data and mathematical symbols (/for “divided by”, * for “multiplied by”, – for “subtraction” and + for “addition”). In the num lock mode, the status light under “num lock” key lights up. When the computer is not in the num Lock mode, the numeric keys can be used to move the cursor and perform other factions, as given below.
– In some programs, the end key moves the cursor to the bottom-right corner of the screen.
– this key moves the cursor down one line.
– The Page down key advances one full screen while the cursor stays at the same place.
– This key moves the cursor one character to the left.
– this key moves the cursor one character to the right.
– in some programs, the home key moves the cursor to the top-left corner of the screen.
– this key moves the cursor one line up.
– the page up key backs up to the previous screen while the cursor stays at the same place.
– the insert key, when toggled off, causes keyed characters to override/affix with the existing characters.
– the delete key deletes a character, space, or selected text.
Extended keyboards include additional keys that duplicate the cursor movement fuctions of the numeric keys. Users who enter a lot of numeric data can leave their computers in the num lock mode and use these additional keys to control the cursor.
The arrow keys, to the left of the numeric keys, move the cursor position, just as the numeric keys 2,4,6, and 8do when they are not in the num lock mode.
Just above the arrow keys are six keys — Insert, Delete, Home, End, Page Up, and Page Down — which duplicate functions of the numeric keys 0, decimal point (Del), 7,1,9, and 3.
– The Print Screen key causes the current screen display to be taken a copy of information or image on the screen.
– the Scroll Lock key causes lines of text images – not the cursor – to move. When the computer is in the scroll Lock mode, the status light under “Scroll Lock” lights up.
– The Pause key causes the screen to pause when information is appearing on the screen too fast to read.
Function Keys
these keys are at the top of a computer keyboard labeled F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12. The functional keys are an easy way to give certain commands to the computer, which are usually operated by keyboard commands. They have different functions in different program. These functions are particularly important in an application program.
Input And Output Devices
Pointing devices: pointing devices control the position of the cursor or pointer on the screen. They include the following:
- Mouse
- Trackball
- Pointing stick
- Touch pad
- Touch screen
- Light pen
- Digitizing/ graphic tablet
- Pen-based system
A brief description is given as under:
Mouse:
a mouse is an input device that device that looks a little bit like a mouse. It has a ball on its underside that is rolled on a flat surface or mouse-pad. The rolling movement causes a corresponding cursor movement on the screen. It enables us to reposition the cursor (or pointer) on the screen where ever we want. It also has buttons on its top which communicate certain commands to the computer while pressed. In particular, button is often used to click on an icon(icon represents a computer activity or command) to invoke the command.
Trackball:
The trackball is a movable ball, on top of a stationary device, that is rotated with fingers or palm of the hand. Its popularity surged with the advent of laptop computers where traveling users found themselves without a flat surface to roll the traditional mouse. It looks like the mouse turned upside down and likewise, has additional buttons whose functions vary depending on the software.
Pointing stick
A pointing stick is a pointing device that looks like a pencil eraser protruding from the keyboard between the G, H, and B keys. we move the pointing stick with our forefinger while using the thumb to press buttons located in front of the space bar. Another device like a pointing stick is the joystick, it is a pointing device that consists of a vertical handle like a gearshift lever mounted on a base with one or two buttons. It is basically used in video games lever mounted on a base with one or two buttons. It is basically used in video games and in some computer-aided design systems.
Touch pad
The touch pad is a small, flat surface over which we slide our finger, using the same movements as we would with a mouse. As we move the finger, the cursor follows the movement. We “click” by tapping the finger on the pad’s surface or by pressing button positioned close by the pad. Touch pads are now common on the portable computers (laptops).
Touch Screen
A touch screen is a video display screen that is sensitized to receive input from simply touching our fingers onto it. It is covered with a plastic layer, behind which are invisible beams of infrared light. We simply touch the provided buttons or menus and get the information on the display screen accordingly.
Light Pen
The light pen is a light-sensitive stylus, or pen-like device, connected by a wire to the computer terminal. The user brings the pen to a desired point on the display screen and presses the pen button, which identifies that screen location to the computer. Engineers, graphic designers, and illustrators use light pens.
Digitizing/Graphic Tablet
A digitizing tablet consists of a tablet connected by a wire to a stylus is a pen-like device with which the user copies an image, such as an architectural drawing or a civil engineering map. A puck looks a bit like a mouse but has different types of buttons and a clear plastic section extending from one end with crosshairs printed on it. The intersection of the crosshairs points to a location on the graphics tablet, which in turn is mapped to a specific location on the screen.
Digitizing tablets are used primarily in design and engineering. When used with drawing and painting software, a digitizing tablet and stylus allow us to do shading and many other effects similar to those artists achieve with pencil, pen, or charcoal. Alternatively, when we use a puck, we can trace a drawing laid on the tablet, and a digitized copy is stored in the computer.
Pen-Based Systems
In the next few years, students may be able to take notes in class without ink and paper, if pen-based computer systems are introduced. These computers use a pen-like stylus to allow people to enter handwriting and marks onto a computer screen rather than typing on a keyboard. This system connects an instructor’s electronic “ whiteboard” on the classroom wall with student’s pen computers, so that the students could receive notes directly, without having to copy information word for word. “ the idea is that the students should concentrate on the lecture listening only”.
Hardware Devices
following are the main hardware devices in any computer system:
- input devices i.e. Keyboards, mouse, Microphones etc.
- output devices i.e. Printers, speakers, monitors etc.
- main memory comprising of RAM and ROM.
- I/O Device i.e. Driver, Terminals, Touch Screen etc.
- Secondary Memory i.e. Hard disk, Floppy disk, Compact disk, Tape etc.
- Inter-connectors i.e. Cables, Ports, Buses etc.
- Networking Devices i.e. Modem, Bridge, Router etc.
Software Classification
Software can be classified into following main two categories:
- System Software
- Application Software
System software: System software is used to control the usage and allocation of different hardware components and enables the other application programs to execute. For example,
- Operating Systems
- Utility Programs (Backup/Restore)
- Drivers
The system software may be a combination of many such programs
Application Software: application software is the software that has been developed to solve a specific problem or to provide audio, video, or multimedia entertainment to the users. It may be categorized as under
- Custom-built
- Packaged
Custom-built software: this is the software that is designed and developed for a particular customer. The custom-built software is discussed in detail in the section 1.6 (systems development).
Packaged software: this software is the kind of off-the-shelf programs or components, developed for sale to the potential software developers/users for their use. The examples are: MS-Word, MS-Power point, Personal Oracle etc. few of these are discussed in the coming chapters.
