ICT CLASS- D&C IN BM,CSCM,D&C IN F&D, D&C SCD,D&C AE, CTGTO JANUARY 2023
ICT DEPARTMENT
TRAINER: MR MWASI MORRIS.
UNIT: ICT
INTRODUCTION TO COMPUTER
COMPUTER is defined as an electronic device or set of device that works under control of installed programs. It accept raw data from outside; it processes the data so as to give out information.
DATA: is any raw fact or figures that may not make sense to the user
INFORMATION: is the processed or refined product that can be understood by the user
QUALITIES OF THE COMPUTER
Automatic: this means that after the computer has been commanded to perform its task it requires minimal human intervention.
Data processor: computer has been designed to receive raw facts and figures that may not be meaningful to the user and then analyses it into information which the user can understand Electronic: computers can be equated to household appliances such as the TV, radio, cameras, etc by the fact that they have capacitors, transistors, chips, circuit boards etc
Accuracy: since they are programmed devices, the writing of the instruction will repeatedly recur Efficiency: compared to any other machine, computer will utilize time and effort to achieve high results
Secrecy: with the use of password
Versatile: Computers are multipurpose, they are compatible to accommodate and operate devices of different technologies e .g: watching T.V
Advantages of computer
- Eases filing system in the office
- Speed
- Enhances communication
- Enhances business
- Enhances education through e learning and e teaching
- Enhances industrial production through computer aided manufacturer(CAM)
- Enhances entertainment
- Create self-employment
Disadvantages of computers
- Expensive
- Cuts down on employment especially when computers are introduced where manual work existed
- Computers needs experts and skills to operate and maintain
- Health hazard e. g back ache, eye sight etc
- Volatile: they can lose huge and crucial information
- Sensitivity to dust, humidity, heat, water
- Addictive especially in games, chatting
- Most computers needs electrical power
- Computer have encouraged laziness due to over reliance
TYPES OF COMPUTERS
Computer may be classified according to functionality, physical size/power processing, and purpose:
1. Functionality
A. Analogue (analog) computers
These computer deal with analog data. Analog data is that which continuous and progressively changes value over time. These computer respond to natural occurrences’ such as temperature, speed and pressure. They may be used in manufacturing industries to check finances condition
B) Digital computer
These computer handle digital data. Digital in that is it discrete. These means the data can be represented as distinct values I.e. 1 or 0
C) Hybrid computer
These kind of computers would handle both analog and digital data.
2. PURPOSE
Under purpose computer there shall be two of them; general purpose and special purpose computers.
A) General purpose computer
Designed to, perform no of tasks, these computer are installed with programs which will enable them to handle a variety of duties. For instance document processing calculation, accounting etc.
b) Special purpose computer
They are designed to perform only one special task. For instance robots in CAMs belongs to this kind of a computer.
3. Physical size
a) Super computer
They are the biggest in size computers. They are fastest in term of speed, the most powerful terms of the tasks they can perform at particular nanosecond and therefore the most expensive only a few nation around the world can afford it. They would be used in complex computer engineering and also serve other small computers in complex network.
b) Main frame computers
They are also very larger, powerful and expensive but lower than super. They are stationary in the control room. They perform complex mathematical calculations. They a large storage capacity and can support a number of peripheral thus require no of people to operate one. They ideal in banks, airport, government, agencies and large organization
c) Mini computers
These are down scaled versions of the mainframe computers. Have less speed, fewer peripherals, less powerful etc. they can be found in research institution, engineering planes, scientific laboratories etc.
d) Micro computers
These consists of relatively small, cheap and not so complicated a computer. They are also transferable. They poses small silicon chip that analysis data. They are generally used in day to day duties in homes, hospitals, schools etc. they are sub grouped into;
Personal computer (PC)
PC is operated by one person for most of it peripheral are single e. g mouse, CPU, keyboard etc. they are usually placed on top of desk when operating thus dubbed desk top computer
Laptop/notebook
These are small convenient and easily portable computer. They are placed on the lap when operating. Laptops are multicolored and bigger than notebook. Most of these computers are extremely expensive due to their convenience, portability and manufacturing technology. They are ideal for use by managers, journalists, researchers etc.
Palmtop computers/PDAs
These are tiny pockets computers usually placed on the palm when operating. In most cases they are incorporated into mobile phones. They are ideal for business executive.
GENERATION OF COMPUTERS
FIRST GENERATION OF COMPUTERS
During the period of 1940 to 1956 first generation of computers were developed. The first generation computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. The vacuum tube was developed by Lee DeForest. A vacuum tube is a device generally used to amplify a signal by controlling the movement of electrons in an evacuated space. First generation computers were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions .
CHARACTERISTICS
1) First generation computers were based on vacuum tubes .
2) The operating systems of the first generation computers were very slow .
3) They were very large in size .
4) Production of the heat was in large amount in first generation computers.
5) Machine language was used for programming .
6) First generation computers were unreliable .
7) They were difficult to program and use.
SECOND GENERATION COMPUTERS
During the period of 1956 to 1963 second generation of computers were developed. The second generation computers emerged with development of Transistors. The transistor was invented in 1947 by three scientists J. Bardeen, H.W. Brattain and W. Shockley. A transistor is a small device made up of semiconductor material like germanium and silicon. Even though the Transistor were developed in 1947 but was not widely used until the end of 50s. The transistor made the second generation computers faster, smaller, cheaper, more energy-efficient and more reliable than their first-generation computers. Even though the transistor used in the computer generated enormous amount of heat which ultimately would lead to the damage of the computers but was far better than vacuum tubes.
Second generation computers used the low level language i.e. machine level language and assembly language which made the programmers easier to specify the instructions. Later on High level language programming were introduced such as COBOL and FORTRAN. Magnetic core was used as primary storage. Second generation computer has faster input /output devices which thus brought improvement in the computer.
CHARACTERISTICS
- Transistors were used in place of vacuum tubes.
- Second generation computers were smaller in comparison with the first generation computers.
- They were faster in comparison with the first generation computers.
- They generated less heat and were less prone to failure.
- They took comparatively less computational time.
- Assembly language was used for programming.
- Second generation computers has faster input/output devices.
THIRD GENERATION COMPUTERS
During the period of 1964 to 1971 Third generation computers were developed. The third generation computers emerged with the development of IC (Integrated Circuits). The invention of the IC was the greatest achievement done in the period of third generation of computers. IC was invented by Robert Noyce and Jack Kilby in 1958-59. IC is a single component containing a number of transistors. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.
Keyboards and monitors developed during the period of third generation of computers. The third generation computers interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory.
CHARACTERISTICS
- IC was used instead of transistors in the third generation computers.
- Third generation computers were smaller in size and cheaper as compare to the second generation computers .
- They were fast and more reliable .
- High level language was developed .
- Magnetic core and solid states as main storage .
- They were able to reduce computational time and had low maintenance cost .
- Input/Output devices became more sophisticated.
FOURTH GENERATION COMPUTERS
After 1971 the fourth generation computers were built. The fourth generation computers were the extension of third generation technology. The fourth generation computers emerged with development of the VLSI (Very Large Scale Integration).With the help of VLSI technology microprocessor came into existence. The computers were designed by using microprocessor, as thousands of integrated circuits were built onto a single silicon chip. What in the first generation filled an entire room could now fit in the palm of the hand. The fourth generation computers became more powerful, compact, reliable and affordable. As a result, they give rise to personal computer (PC) revolution .
For the first time in 1981 IBM introduced its computer for the home user and in 1984 Apple
introduced the Macintosh Microprocessor .
CHARACTERISTICS
1) The fourth generation computers have microprocessor-based systems .
2) They are the cheapest among all the computer generation .
The speed, accuracy and reliability of the computers were improved in fourth generation computers.
Many high-level languages were developed in the fourth generation such as COBOL, FORTRAN, BASIC, and PASCAL and C Language.
4) A Further refinement of input/output devices was developed .
5) Networking between the systems was developed .
IBM 4341, DEC 10, STAR 1000, PUP 11 and APPLE II are the examples of fourth generation computers.
FIFTH GENERATION COMPUTERS
Fifth generation computers are in developmental stage which is based on the artificial intelligence. The goal of the fifth generation is to develop the device which could respond to natural language input and are capable of learning and self-organization. Quantum computation and molecular and nanotechnology will be used in this technology. So we can say that the fifth generation computers will have the power of human intelligence.
CHARACTERISTICS
1) The fifth generation computers will use super large scale integrated chips .
2) They will have artificial intelligence .
3) They will be able to recognize image and graphs .
4) Fifth generation computer aims to be able to solve highly complex problem including decision
making, logical reasoning .
5) They will be able to use more than one CPU for faster processing speed .
6) Fifth generation computers are intended to work with natural language
THE COMPUTER SYSTEM
Computer system comprises of all the parts that make computer
phenomenon. There three major parts of computer system:
HARDWARE
Physical or tangible components of the computer are referred to as hardware. When the computer is shut off, the hardware would remain visible. Hardware are sub grouped into four components namely;
CPU (processor)Input devicesOutput devicesStorage devicesCPU (central processing unit)
CPU also referred as the processor, is a small silicon chip housed inside the system unit of a micro-computer which analyses raw data into information. It has been dubbed the computer ‘brain’ for it coordinates all the activities in the computer. The speed of the CPU is very important for it determine the time to be taken and the amount of task to be carried out by the computer modem CPUs range from P1-P4; whereby P4 is fastest. All input, output and peripherals must be attached to the CPU via the motherboard of the system unit.
The CPU is sub-divided into three smaller areas;
- Control unit (CU)
- Arithmetic and logical unit (ALU)
- Main memory
Main memory Control unit (CU) Receive and analyses/interprets all instruction into the computer. Also delegates duties to all other parts in the computer
An ordinary mouse has a rubber ball at its underside. The ball rolls in
relation to how the device is moved on a surface. There are two rollers that
touch the ball and they roll as the ball moves. Next to each roller is a sensor
that checks the distance travelled, the direction moved and the speed of the
mouse pointer on the screen.
Techniques or action of the mouse
When the computer is operated and the mouse is used, one or more of the
actions below must be applied.
1. Click
This is briefly to press and release a mouse button
so as to issue a command or select an item.
2. Double click
This is consecutively pressing LMB twice in order to issue command; i. e
to open an item or to highlight a word
3. Triple click
This is giving three consecutive taps to the LMB twice in order to issue
command I. e to highlight paragraph or an entire document.
4. Right click
This is briefly pressing the RMB (inactive button) on an item or on an
area in order to retrieve commands for application.
5. Click away
It is pointing and clicking the active mouse button outside a selection
or a displayed menu in order to deselect or to do away with it.
6. Point / select
This is to move mouse pointer on an item then click
the LMB
7. Drag/drop
This is to point, press and hold down the LMB on an
item to move it from a position to another
8. Highlight
This is to point and drag over a text so as to select the textual data for
particular aspect.
9. Position cursor/ insertion point
It point
between the characters so as to type a character
10. Resize objects
This is to point border handles of an objects and
drug so as to increasing and decreasing its size
11. Move/position object
This is
to point and drug the object from one position to another
THE KEYBOARD
It is another input device used to enter textual data through typing in
to the computer. It can also be used to enter commands and instruction in the
computer by pressing the keys. The keys of the keyboard may be sub-
The alphabets I. e (grouped into the following categories:
1. ALPHA NUMERIC KEYS
These
consist of;
A-Z)
The numerals I. e (0-9)
The punctuation marks I. e (,.; :”)
The mathematical The symbols I. e (# @ %)
operator
I. e (+-=/)
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