The document discusses the main components of a computer system. It describes the three main parts of a computer as the input unit, central processing unit (CPU), and output unit. The CPU is further divided into the control unit, arithmetic logic unit (ALU), and memory unit. The input unit allows data to enter the computer via devices like a keyboard, mouse, and scanner. The output unit displays results and uses devices like a monitor and printer. Proper software like an operating system and additional utilities is also needed to make the computer functional.

4.  1) Speedy and accurate calculations.
 2) Storage of information.
 3) Retrieval of information .
 4) Combination of information.
 5) Sorting information.
 6) processing of information.

5. On the basis of its internal structure, a computer can
be divided into the following three main parts :
1. Input Unit
2. Central Processing Unit
3.Output Unit

8.  Through input unit data is feed into the
computer. Key board and mouse are the
main input medium.
 The common input devices are listed
below.
 (Keyboard, mouse ,scanner,CD rom
drive,DVD romdrive,floppy disk
drive,tracker ball,memory card
reader,external hard disk,joystick,(OCR)
optical card reader,(MCR) magnetic card
reader,(OMR) optical mark reader.)

12.  Central processing unit is the major part of the computer.
This part of the computer controls all the functions of the
computer, as the brain of the computer. It is the most
important part of the computer and the costliest
peripheral of the system
 the CPU is divided into three parts :
 1) Control unit.
 2) Arithmetical logic unit (ALU).
 3) Memory unit.

13.  Control unit, as evident from the name, controls the
working of the computer and ascertains whether the
computer is functioning as per the commands given to it
by the user or not. This part is located between Memory
unit and Arithmetical logic unit. The data can be
transferred between them through this unit. In general it
can be considered as the brain of the computer.

14.  The function of this unit is to verify the accuracy of the
data received from memory unit and transfers the same
back to the main memory of the computer. This part
performs all the arithmetical and logical functions.

15.  Memory unit is also the most important parts of the
computer. This unit stores all the data, calculations and
results into it and In case of need it sends the data in the
form of output. Memory unit transfers the data to the
Arithmetical and logic unit.
 Memory may be volatile or non volatile in nature.
 1)Volatile memory: it is washed as soon as the power is
cut. The information and data is also as soon as the power
supply is stopped. e.g.(RAM)
 2)Non volatile memory: it is not washed if the power
supply is cut and hence the data and information are safe
in the memory. e.g. (ROM) I.e. hard disk.

17.  Through the output unit the results and feedback
are seen from the computer. Through the output
data the operator gets the result of his work. The
output unit confirms that the function or
command has completed successfully or not.
 The monitor is the main output unit.
 Other examples of output unit are ( printer,TFT
and CRT monitors, desktop speakers,head
sets,projector etc.)

19.  The computer CPU is the most important
part of the computer. The CPU is the base
of all the computer hardware
 The computers mother board,
processor,and all other hardware like the
CD/DVD writer,HDD,etc are integrated in
a systematic order.
 It is a very sensitive device and thus requires
proper care ,handling ,proper
environmental conditions and proper air
circulation for its optimum and efficient
functioning.

20.  The computer mother
board is the major base
where all the computer
circuitry is build. All the
other hardware like the
CD- drive, DVD-drive,
floppy drive, hard disk,
SMPS (power
supply),RAM, modem,
sound card, graphics
cards,etc are attached on it

21.  The processor is mounted on the mother
board. The processor analyses and
processes and manages all the data and
actions that are occurring in the computer.
It plays managerial role in the system.
 The processor generates a lot of heat so it
is accommodated with a heat sink fan.
Which removes excess of heat from the
system. Thus preventing any sort of
damage to the system

22.  Based on the concept of
volatile and non volatile
memories there are two kinds
of memory in the computer
RAM(random access memory)
and ROM (read only
memory).
 RAM- e.g. SD RAM,DDR RAM,
DDR-2RAM.these all are
volatile in nature.
 ROM- e.g. IDE hard disk, Sata
hard disk,flash disk and
external hard disk.

23.  These are also considered as memory devices as the also
are used to feed and retrieve data and information
from the computers. They are known as an input and
output medium.
 The use of the floppy has been stopped in the recent
years due to new and advanced DVD and CD drives that
have massive storage capacities as compared to the
floppies
 and are much cheaper and handy to use for storing
data.

24.  A 3.5” floppy has a storing space of 720 kb to 1.44 Mb.
 A 3.5” drive cost RS 350 to 400.
 A 3.5” floppy costs RS 12/-

25.  A CD (compact disk )has a space of 700MB
 a CD disk drive (read only) is not available now
because it is out dated .
 a CD writer casts RS 700/-
 a blank CD costs RS 10/-and a re-writable CD costs
RS 35 to 45/- .
 A CD burns at a max speed of 52 X. RRW CD at 10X
max.

26.  A DVD (digital video disk ) has a space of 4.7GB
 A DVD writer costs RS 1250 to 1300/- this is the latest
DVD drive that is in markets today it can read as well as
write a DVD. Older versions were DVD combo and DVD
reader.
 A blank DVD is of RS 15 to 20/-
 A re- writable DVD costs RS 80/-
 A DVD burns at a max speed of 16x and a RRW DVD
burns at a max speed of 10x

27.  There are primarily two kinds of hardware
expansion slots on the mother boards :
 1) 32- bit PCI slots these accommodate
internal hardware like sound card,T.V
tuner card,modem,etc.
 2) 8x AGP slot they are used to increase the
systems video ram which is required in
playing hi graphic games and in operating
animating software .they accommodate
graphic cards up to 512 MB of video ram.

29.  Graphic cards are very popular among
extreme gamers and animators these
cards are having video memory (V-
RAM) ranging from 128MB to 1GB.
 Popular graphic card vendors are
NVIDIA and ATI RADEON.

32.  The SMPS unit supplies the necessary amount of power to the
mother board and its corresponding hardware devices like the
CD, DVD writers,floppy drives, hard disks,memory modules
(RAM),PCI,8x AGP hardware modules,the system processor and
to the heat sink fans.
 Different SMPS provide different range of power to the system.
Their power ranges from 250W to 450W watt depending on your
power requirement you can install the desired SMPS for your
system.
 The system requires the correct amount of electricity undesired
amount may damage the mother board or its complex
circuitry.thus the SMPS works as a step down transformer and
protects the computer and is indispensable for normal
functioning of the computer.

34.  After the hardware configuration is properly verified it is
important that we should also know about the software.
 What is software?. The question may have many answers for
a layman.
 Software may simply be defined as the sole of the computer.
The software makes the hardware work together in a
coordinative manner to accomplish a task that is directed by
the user.
 Just like the human body is nothing without its sole in the
similar manner a computer and its hardware is meaning less
without its operating software and other software.

35. In addition to the hardware you should also
have the following software installed on your
system for enjoying a perfect computing
experience.
1) The windows operating system (OS) such
as Windows 98,Windows Xp or Windows
Vista.
2) The Microsoft Office suit. Perhaps MS
Office 2003 or MS office 2007.
3) All driver software for the hardware items
such as drivers for the CD-ROM, Graphics
card, modem, sound card etc.
4) Any additional utility like Anti virus,
Adobe Photoshop and acrobat
reader,Pagemaker,Corol draw,Nero,Jet
audio etc.