Define analog and digital computer. List the important characteristics of the computer.

Subject Introduction to Computer System
NU Year Set: 1.(a) Marks: 2+4=6 Year: 2013

Analog computers operate on mathematical variables in the form of physical quantities that are continuously varying. For example temperature, pressure, voltages, etc. The basis of the working of the analog computers is modeling. Any real physical process can always be replaced by a mathematical model having the same properties.

Digital computer is that computer, which performs and accepts the converted binary number data. Today most of the computers are digital computers. It is basically an electronic based computer. Rather than continuous its input functions works discretely. Input can be in form of letters, numbers written and represented in special binary coded languages. Micro computers, personal computers, network servers, super computers and multi processor computers are kinds of digital computer. It uses two binary code or digits 0 and 1, which stands for no and yes, false and true , left and right. All instructions given to computer are performed through these two digits.

Basic characteristics about computer are:

1. Speed: - As you know computer can work very fast. It takes only few seconds for calculations that we take hours to complete. You will be surprised to know that computer can perform millions (1,000,000) of instructions and even more per second.

Therefore, we determine the speed of computer in terms of microsecond (10-6 part of a second) or nanosecond (10 to the power -9 part of a second). From this you can imagine how fast your computer performs work. 

2. Accuracy: - The degree of accuracy of computer is very high and every calculation is performed with the same accuracy. The accuracy level is 7.

determined on the basis of design of computer. The errors in computer are due to human and inaccurate data.

3. Diligence: - A computer is free from tiredness, lack of concentration, fatigue, etc. It can work for hours without creating any error. If millions of calculations are to be performed, a computer will perform every calculation with the same accuracy. Due to this capability it overpowers human being in routine type of work.  

4. Versatility: - It means the capacity to perform completely different type of work. You may use your computer to prepare payroll slips. Next moment you may use it for inventory management or to prepare electric bills.

5. Power of Remembering: - Computer has the power of storing any amount of information or data. Any information can be stored and recalled as long as you require it, for any numbers of years. It depends entirely upon you how much data you want to store in a computer and when to lose or retrieve these data.  

6. No IQ: - Computer is a dumb machine and it cannot do any work without instruction from the user. It performs the instructions at tremendous speed and with accuracy. It is you to decide what you want to do and in what sequence. So a computer cannot take its own decision as you can. 

7. No Feeling: - It does not have feelings or emotion, taste, knowledge and experience. Thus it does not get tired even after long hours of work. It does not distinguish between users.

8. Storage: - The Computer has an in-built memory where it can store a large amount of data. You can also store data in secondary storage devices such as floppies, which can be kept outside your computer and can be carried to other computers.


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