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Dec 12, 2015
Lecture-01 Computer Fundamentals
Computer is an advanced electronic device that takes raw data as input from the user and processes these data under the control of set of instructions (called program) and gives the result (output) in a useful format and saves output for the future use. It can process both numerical and non-numerical (arithmetic and logical) calculations. The basic components of a modern digital computer are: Input device, Output device, Central Processing Unit (CPU) ahd Storage device. Computer cannot do anything without a Program.
The term computer is derived from the Latin term "Computare", this means to calculate. Computers were originally invented to do fast and accurate computations -hence the name "computers."
Cha.rles Babbage is called the Father of the computer. The first mechanical computer designed by Charles Babbage was called Analytical Engine. It uses read-only memory in the form of punch cards.
1.2. Classification of computers: . Computers differ based on their data processing abilities. They are classified according to purpose, data handling and functionality. There are many computers which are different from each other in various aspects.
Classification of Computers
Fig.1: Classification of computers
1.2.1 According to technology /functionality: According to functionality, computers are classified as:
a) Analog Computer: An analog computer (spelt analogue in British English) is a form of computer that uses continuous physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved.
b) Digital Computer: A computer that performs calculations and logical operations with quantities represented as digits, usually in the binary number system.
c) Hybrid Computer (Analog+ Digital): A combination of computers those are capable of inputting and outputting in both digital and analog signals. A hybrid computer system setup offers a cost effective method of performing complex simulations.
1.2.2 According to Purpose Computers may be utilized for either special or general purposes.
a) General-Purpose Computers: These machines have the capability of dealing with variety of different problems, and are able to act in response to programs created to meet different needs. A general-purpose computer is one that has the ability to store different programs of instruction and thus to perform a variety of operations.
b) Special-Purpose Computers: as to the name implies, is designed to perform one specific task. The program of instructions is built into, or permanently stored in the machine. Specialization results in the given task being preformed very quickly and efficiently. Most special purpose computers have the capability of performing just one task. They are frequently referred to us "dedicated," because of their limitations to the specific task at hand.
1.2.3 On the basis of size and performance: There are four main classifications of computers on the basis of their size and performance. They are as under:
Micro computer Mini computer Mainframe computer Super computer
Here is a brief breakdown of each:
(1) Micro computers: These computers use a microprocessor chip and this chip is used instead of CPU means that this microprocessor chip works as a CPU. Only one user uses these computers at time that's why they are also known as personal computers. Two major types of these computers are Laptop or Desktop computers.
The Micro computers are also further classified as under: Desktop Computer: a personal or micro-mini computer sufficient to fit on a
desk. Laptop Computer: a portable computer complete with an integrated screen
and keyboard. It is generally smaller in size than a desktop computer and larger than a notebook computer.
Palmtop Computer/Digital Diary /Notebook / Personal Digital Assistants (PDAs): a hand-sized computer. Palmtops have no keyboard but the screen serves both as an input and output device.
(2) Mini Computers: These computers fall in the gap between micro computers and mainframe computers. They possess much more power than a micro-computer, but not enough to perform the tasks of a mainframe computer. These computers were developed in 1960s at that time mainframe computer was very costly. Mini computers were available in cheap prices, so users start using it and gradually became less expensive as time moved on and technology became more widely available.
(3) Mainframe Computer: Mainframe computers are extremely powerful and large computers that have the capacity to process the activity of multiple users at one time. Many other smaller, less powerful computers (known as terminals) are networked with the mainframe, meaning they are attached to the central mainframe computer. The mainframe has the capability to process and store things that come from the connected terminals. By using terminal users put inputs into the computer and get the output through screen.
N.B.: Terminal is a device which has keyboard and a screen.
(4) Super Computers: Super computers are the most powerful computers. It can perform billions of instructions per second and may have ability of 40000 microcomputers. It calculated the value of Pi to 16 million decimal places. Its cost is 15-20 million dollars. Used for weather forecasting, nuclear science research, aerodynamic modeling, metrology, seismology etc. Examples are: CRAY X-MP-14, PARAM, PACE etc. Size, speed and cost of the super computers are greater than the micro, mini and main frame computers.
* Embedded Computer: The smallest computer (A special-purpose computer system) embedded within the appliance. Like Televisions, Digital Video Recorder, Digital camera, Washing machines, Watches, etc.
1.3 Uses of a computer: A computer is used in all human life: It has revolutionized all phases of human activities. The most important have been given as follows:
1) Routine job handling: The routine classical and stenotype jobs calculating and formality bits, salaries, updating stocks, tax return, reservation records and information.
2) Traffic control: Controlling traffic, traffic lights. Television cameras are used to maintain traffic light routine.
3) Electronic money: Automatic tellers machine (ATM) is very common in banks. You can deposit and withdraw money with the ATM.
4) Electronic office: All type information are stored, manipulated and utilized in the electronic form. A document is sent to different place with FAX, internet and e-mail.
5) Industrial Application: It plays an important role in production control. It is bringing efficiency it trade and industry.
6) Telephones: With help computerized telephone through satellites STD and IST services have been introduced. It maintains the record of calls and does the billing for you.
7) Trade: Every type of trade computer is used successfully. It 1s used m Banks, stock exchanges to control stocks and accounts.
8) Scientific research: In every science, the research work becomes economical from time, energy, money point of new. A large data is analyzed very quickly.
9) Medicine: There is wide use in medical science e. g. ECG, CAT scan, Ultra sound. The proper and accounts diagnosis is done with the help of computer. The medical apparatus are controlling computerized.
10) Space Science: The satellite controlling I the space with the help of computer. The information's are collected by using the computer from the space satellite.
11) Publication: The composing work is done speedily and economical with the help of computer. The designing work is also done by computer. The quality is maintained is publication by computer.
12) Communications: The computer is used for sending message example printer, FAX, e-mail, Internet. The import and export work is done on internet.
13) Film industry: It had influenced film industry such as animation; titeling etc.The multimedia approach is used in film production with the help of computer. The cartoon films are developed by computers.
14) Education: The computer is widely used in the field of education and independent study field of computer science has developed which is popular these days. At every stage computer is compulsory. The distance education is using computer for instructional purpose as multimedia approach. The computer makes teacher learning process effecting by involving audio and visual sense of learners.
1.4 Generation of computers
The history of computer development is often referred to in reference to the different generations of computing devices. Each of the five generations of computers is characterized by a major technological development that fundamentally changed the way computers operate, resulting in increasingly smaller, cheaper, more powerful and more efficient and reliable computing devices.
Based on the characteristics of various computers developed from time to time, they are categorized as the following five generation of computers.
Thi~ .. . GeneraUor:t
Each of the five generations of computers is characterized by a major technological development that fundamentally changed the way computers operate.
1. First Generation (1940-1956) Vacuum Tubes
The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was