COMPUTER PROGRAMMING GE6151 Unit 1

1. Define computer. Explain the characteristics briefly? (MAY 2009\FEB 2009)

A computer is a programmable machine or device that performs pre-defined or programmed computations or controls operations that are expressible in numerical or logical terms at high speed and with great accuracy.

Characteristics of Computers

· Speed

· Accuracy.

· Automation.

· Endurance.

· Versatility.

· Storage.

· Cost Reduction.

2. With suitable examples, explain about Number systems. (JAN 2009)

A number system is a set of rules and symbols used to represent a number. There are several different number systems. Some examples of number systems are as follows:

· Binary (base 2)

· Octal (base 8)

· Decimal (base 10)

· Hexadecimal (base 16)

Decimal and Hexadecimal numbers can each be represented using binary values. This enables decimal, hexadecimal, and other number systems to be represented on a computer which is based around binary (0 or 1 / off or on). The base (or radix) of a number system is the number of units that is equivalent to a single unit in the next higher counting space. In the decimal number system, the symbols 0-9 are used in combination to represent a number of any sizes.

For example, the number 423 can be viewed as the following string of calculations: (4 x 100) + (2 x 10) + (3 x 1) = 400 + 20 + 3 = 423

3. Describe evolution of computer? (JAN 2009 / MAY 2009)

· Abacus

· Astrolabe

· Pascaline

· Stepped Reckoner

· Difference Engine

· Analytical Engine

· Punch Cards

· ENIAC (Electrical Numerical Integrator and Calculator)

· Von Neumann Machine

4. Explain various generations of computers with features? (FEB 2009/FEB 2010)

Generation of Computers

Each phase of computer development is known as a separate generation of computers. The computer can be classified into four generations according to their type of electronic circuits such as vacuum tube, transistor, IC etc.

(a) The First Generation Computers (1949-55)

Main Features:

1) The computers of this generation used vacuum tubes.

2) These computers used machine language for giving instructions.

3) They used the concept of stored program.

4) These computers were 5000 times faster than the MARK-I.

5) The first generation computers were welcomed by Government and Universities.

Limitations:

1) These computers were very big in size. The ENIAC machine was 30 x 50 feet in size and

30 tons in weight. So, these machines required very large space for their workings.

2) Their power consumption was very high.

3) These computers had slow operating speed and small computing capacity.

4) These computers had a very small memory.

(b) The Second Generation Computers (1956-65) Main Features:

1) The computers of this generation replaced vacuum tubes with transistors.

2) Magnetic cores were invented for storage.

3) Different magnetic storage devices were developed in this generation.

4) Commercial applications were developed during this period. Eighty percent of these computers were used in business and industries.

(c) Third Generation Computers (1966-75)

 Main Features:

· The third generation computers replaced transistors with‟ Integrated Circuits‟. These

Integrated Circuits are also known as chips.

· The size of main memory was increased and reached about 4 megabytes.

· Magnetic disk technology had been improved and drive having capacity upto 100

MBPS came into existence.

· The CPU becomes more powerful with the capacity of carrying out 1 million instructions per

second.

· This generation computers were relatively inexpensive and faster.

· The application area also increased in this generation. The computers were used in other areas like education, small businesses survey, analysis along with their previous usage areas.

(d) The Fourth Generation Computers (1976-Present) 

Main Features:

i.The fourth generation computers replaced small scale integrated circuits and medium scale integrated circuits with the microprocessors chip.

ii. Semiconductor memories replaced magnetic core memories.

iii. The hard-disks are available of the sizes upto 200 GB. The RAID technology

(Redundant Array of Inexpensive Disks) gives storage upto thousands of GB. iv. Computer cost came down rapidly in this generation.

v. Application of computers is increased in various areas like visualization, parallel computing, multimedia etc.

(e) The Fifth Generation Computers

Mankind along with the advancement in science and technology is working hard to bring the Vth Generation of computer. These computers will have the capability of thinking on their own like an man with the help of Artificial Intelligence (AI). the 21st century will be better, faster, smaller and smarter computers.