Concept of Computer System:-
A computer is
an advanced electronic device that takes raw data as input from the user and
processes this data under the control of set of instructions (called program)
and gives the result (output) and saves output for the future reference and
usage.
C - Commonly;
O - Oriented; M - Machine; P - Particularly; U - Used; T - for Trade; E -
Education; R - and Research.
To know about
the working of a computer, first need to understand various terms such as Data,
Processing and Information. First of all, lets start with three basic terms:-
1. Data: Data is a collection of basic facts and figure without any
sequence. This data is also called as raw data. When the data is collected as
facts and figures, there is no meaning to it, at that time, for example, name
of people, names of employees etc.
2. Processing: Processing is the set of instructions given by the user to
the related data that was collected earlier to output meaningful information.
The computer does the required processing by making the necessary calculations,
comparisons and decisions.
3. Information: Information is the end point or the final output of any
processed work. This meaningful output data is called information.
Characteristics of Computer:-
The major
characteristics of computers are the following:
- Speed: A powerful computer is capable of executing about 3
million calculations per second.
- Accuracy: A computer’s accuracy is consistently high; if there
are errors, they are due to errors in instructions given by the
programmer.
- Reliability: The output generated by the computer is very reliable
as long as the data is reliable.
- Memory/Storage Capacity: The computer can store large
volumes of data and makes the retrieval of data an easy task.
- Versatility: The computer can accomplish many different things. It
can accept information through various input-output devices, perform
arithmetic and logic operations, generate a variety of outputs in a variety
of forms, etc.
- Automation: Once the instructions are fed into computer it works
automatically without any human intervention.
- Diligence: A computer will never fail to perform its task due to
distraction or laziness.
- Convenience: Computers are usually easy to access, and allow people
to find information easily that without a would be very difficult.
- Flexibility: Computers can be used for entertainment, for business,
by people who hold different ideals or who have varied goals. Almost
anyone can use a computer, and computers can be used to assist with almost
any goal.
Goals of Computers:-
1. Problem-solving techniques using the computer.
2. Analysis of complex problems and the synthesis of solutions .
3. Comprehension of modern software engineering principles.
4. A vast breadth and depth of knowledge in the discipline of
computer science.
Types of computers:-
Computers
range in size and capability. At one end of the scale are supercomputers, very
large computers with thousands of linked microprocessors that perform extremely
complex calculations. At the other end are tiny computers embedded in cars,
TVs, stereo systems, calculators, and appliances. These computers are built to
perform a limited number of tasks.
Desktop computers
Desktop
computers are designed for use at a desk or table. They are typically larger
and more powerful than other types of personal computers. Desktop computers are
made up of separate components. The main component, called the system unit, is
usually a rectangular case that sits on or underneath a desk. Other components,
such as the monitor, mouse, and keyboard, connect to the system unit.
Laptops
Laptops are
lightweight mobile PCs with a thin screen. Laptops can operate on batteries, so
you can take them anywhere. Unlike desktops, laptops combine the CPU, screen,
and keyboard in a single case. The screen folds down onto the keyboard when not
in use.
Handheld computers (PDA)
Handheld
computers, also called personal digital assistants (PDAs), are battery-powered
computers small enough to carry almost anywhere. Although not as powerful as
desktops or laptops, handheld computers are useful for scheduling appointments,
storing addresses and phone numbers, and playing games. Some have more advanced
capabilities, such as making telephone calls or accessing the Internet. Instead
of keyboards, handheld computers have touch screens that you use with your
finger or a stylus (a pen-shaped pointing tool).
