Computer Systems
A computer is a programmable machine that receives input from input
devices, stores and manipulates data using memory, storage medium and CPU, and
provides output in a useful format using output devices.
A computer is an electronic device, which executes software
programs. It consists of 2 parts - Hardware and Software.
A computer is an electronic device
used to process data. A computer can convert data into information that is
useful to people.
A
complete computer system includes four distinct parts:
o Hardware
o Software
o Data
o User
The computer system includes not only the
computer, but also any software and peripheral devices that are necessary to
make the computer to function.
Computer System is group of hardware components and associated
software, designed and assembled to perform a specific function or group of
functions.
Computer System is a programmable machine. The two
principal characteristics of a computer are:
1.
It
responds to a specific set of instructions in a well-defined manner.
2.
It
can execute a prerecorded list of instructions.
All general-purpose computers require the following hardware components:
2. Mass storage device:
Allows a computer to permanently retain large amounts of data. Common mass
storage devices include disk
drives and tape drives.
3. Input device :
Usually a keyboard and mouse,
the input device is the conduit through which data and instructions enter a
computer.
4. Output device : A
display screen, printer,
or other device that lets you see what the computer has accomplished.
5. Central processing unit (CPU):
The heart of the computer, this is the component that actually executes
instructions.
Figure 1.1: Block diagram
of Computer
In addition to these components, many
others make it possible for the basic components to work together efficiently.
For example, every computer requires a bus
that transmits data from one part of the computer to another.
Computers can be generally classified by
size and power as follows, though there is considerable overlap:
o
Personal computer :
A small, single-user computer based on a microprocessor. In addition to the
microprocessor, a personal computer has a keyboard for entering data, a monitor
for displaying information, and a storage device for saving
data.
o
Workstation : A
powerful, single-user computer. A workstation is like a personal computer, but
it has a more powerful microprocessor and a higher-quality monitor.
o
Minicomputer : A multi-user
computer capable of supporting from 10 to hundreds of users simultaneously.
o
Mainframe : A
powerful multi-user computer capable of supporting many hundreds or thousands
of users simultaneously.
o
Supercomputer :
An extremely fast computer that can perform hundreds of millions of
instructions per second.
The computer processes input through input devices like mouse and
keyboard. The computer displays output through output devices like color
monitor and printer.
Figure 1.3: Abstract view of Computer System
Modern computers are electronic and digital.
The actual machinery -- wires, transistors,
and circuits -- is called hardware; the instructions and data
are called software.
Computer is a
programmable device that performs mathematical calculations and logical
operations, especially one that can process, store and retrieve large amounts
of data very quickly.
Computer is Electronic machine capable of performing
calculations and other manipulations of various types of data, under the
control of a stored set of instructions. The machine itself is the hardware;
the instructions are the program or software.
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