A computer consists of both hardware and software. The hardware includes the system unit containing the CPU and RAM, a monitor to display visual output, a keyboard and mouse for input, and peripheral devices like printers and scanners. The software includes operating systems that manage computer resources and provide common services, application software that helps users perform tasks, and compiler software that converts programs into machine-readable format.

3. What is a Computer???
A computer is a general purpose device that can
be programmed to carry out a finite set of arithmetic
or logical operations. Since a sequence of
operations can be readily changed, the computer can
solve more than one kind of problem.
Conventionally, a computer consists of at least one
processing element and some form of memory. The
processing element carries out arithmetic and logic
operations, and a sequencing and control unit that
can change the order of operations based on stored
information. Peripheral devices allow information to
be retrieved from an external source, and the result
of operations saved and retrieved.

4. Monitor
CPU
Speaker
Keyboard Mouse

5. Computers can be generally classified by size and power
as follows, though there is considerable overlap:
Personal computer: A small, single-user computer based
on a microprocessor.
Minicomputer: A multi-user computer capable of
supporting up to hundreds of users simultaneously.
Mainframe: A powerful multi-user computer capable of
supporting many hundreds or thousands of users
simultaneously.
Supercomputer: An extremely fast computer that can
perform hundreds of millions of instructions per second.

7. Input Devices
An input device is any peripheral (piece
of computer hardware equipment) used to
provide data and control signals to
an information processing system such as
a computer or other information appliance.
Input and output devices make up the
hardware interface between a computer and
a scanner or 6DOF controller.

8. Output Devices
An output device is any piece of computer hardware
equipment used to communicate the results of data
processing carried out by an information processing
system (such as a computer) which converts the
electronically generated information into human-readable
form. There are many input and output devices such
as multifunction printers and computer-based navigation
systems that are used for specialised or unique
applications.
In computing, input/output, or I/O, refers to the
communication between an information processing
system (such as a computer), and the outside world.
Inputs are the signals or data received by the
system, and outputs are the signals or data sent from it.

9. Parts of a Computer!!!
If you use a desktop computer, you might already know
that there isn't any single part called the "computer." A
computer is really a system of many parts working
together. The physical parts, which you can see and
touch, are collectively called hardware. (Software, on the
other hand, refers to the instructions, or programs, that
tell the hardware what to do.)
The illustration below shows the most common
hardware in a desktop computer system. Your system
may look a little different, but it probably has most of
these parts. A laptop computer has similar parts but
combines them into a single notebook-sized package.

10. Parts of a Computer!!!

11. System Unit
• The system unit is the core of a computer system. Usually it's a
rectangular box placed on or underneath your desk. Inside this
box are many electronic components that process information.
The most important of these components is the central
processing unit (CPU), or microprocessor, which acts as the
"brain" of your computer. Another component is random
access memory (RAM), which temporarily stores information
that the CPU uses while the computer is on. The information
stored in RAM is erased when the computer is turned off.
• Almost every other part of your computer connects to the
system unit using cables. The cables plug into
specific ports (openings), typically on the back of the system
unit. Hardware that is not part of the system unit is sometimes
called a peripheral device or device.

12. System Unit

13. Monitor
A monitor or display (also called screen or visual display
unit) is an electronic visual display for computers. The
monitor comprises the display device, circuitry, and an
enclosure. The display device in modern monitors is
typically a thin film transistor liquid crystal display(TFT-
LCD) thin panel, while older monitors use a cathode ray
tube (CRT) about as deep as the screen size.
Originally, computer monitors were used for data
processing while television receivers were used for
entertainment. From the 1980s onwards, computers (and
their monitors) have been used for both data processing and
entertainment, while televisions have implemented some
computer functionality. The common aspect ratio of
televisions, and then computer monitors, has also changed
from 4:3 to 16:9 (and 16:10).

14. Monitor

15. Keyboard
In computing, a keyboard is a typewriter-style device, which uses an
arrangement of buttons or keys, to act as mechanical levers or electronic
switches. Following the decline of punch cards and paper tape, interaction
via teleprinter-style keyboards became the main input device for computers.
Despite the development of alternative input devices, such as
the mouse, touch screen, pen devices, character recognition and voice
recognition, the keyboard remains the most commonly used and most
versatile device used for direct (human) input into computers.

16. Keyboard

17. Mouse
A mouse is a pointing device that functions by
detecting two-dimensional motion relative to its
supporting surface. Physically, a mouse consists
of an object held under one of the user's
hands, with one or more buttons.
The mouse sometimes features other
elements, such as "wheels", which allow the user to
perform various system-dependent operations, or
extra buttons or features that can add more control
or dimensional input. The mouse's motion typically
translates into the motion of a pointer on
a display, which allows for fine control of
a graphical user interface.

18. Mouse

19. Printer
A printer is a peripheral which produces a text or graphics of
documents stored in electronic form, usually on physical print
media such as paper or transparencies. Many printers are
primarily used as local peripherals, and are attached by
a printer cable or, in most new printers, a USB cable to a
computer which serves as a document source.
In addition, a few modern printers can directly interface to
electronic media such as memory cards, or to image capture
devices such as digital cameras and scanners; some printers
are combined with scanners or fax machines in a single
unit, and can function as photocopiers. Printers that include
non-printing features are sometimes called multifunction
printers (MFP), multi-function devices (MFD), or all-in-one
(AIO) printers. Most MFPs include printing, scanning, and
copying among their many features.

20. Printer

21. Scanner
• An image scanner—often abbreviated to just scanner—
is a device that optically scans images, printed
text, handwriting, or an object, and converts it to
a digital image. Common examples found in offices are
variations of the desktop (or flatbed) scanner where the
document is placed on a glass window for scanning.
• Hand-held scanners, where the device is moved by
hand, have evolved from text scanning "wands" to 3D
scanners used for industrial design, reverse
engineering, test and measurement, orthotics, gaming
and other applications.
• Mechanically driven scanners that move the document
are typically used for large-format documents, where a
flatbed design would be impractical.

22. Scanner

23. Speaker
Computer speakers, or multimedia
speakers, are speakers external to a computer, that disable the
lower fidelity built-in speaker. They often have a low-power
internal amplifier. The standard audio connection is a 3.5 mm
(approximately 1/8 inch) stereo jack plug often colour-coded
lime green (following the PC 99 standard) for computer sound
cards.
A plug and socket for a two-wire (signal and ground) coaxial
cable is widely used to connect analogue audio and video
components. Rows of RCA sockets are found on the backs of
stereo amplifier and numerous A/V products. The prong is 1/8"
thick by 5/16" long. A few use an RCA connector for input.
There are also USB speakers which are powered from the
5 volts at 500 milliamps provided by the USB port, allowing
about 2.5 watts of output power.

24. Speaker

26. Software
Computer software is a collection
of computer program and
related data that provides the
instructions for telling a computer what
to do and how to do it.
Software refers to one or more
computer programs and data held in the
storage of the computer for some
reasons.
In other words, software is a set
of programs, procedures, algorithms and
its documentation concerned with the
operation of a data processing system.

27. Types of Software
There are mainly three
types of Software:
1.Operating system
2.Application
Software
3.Compiler Software

28. Operating System
An operating system (OS) is a
collection of software that
manages computer hardware resources
and provides
common services for computer programs.
The operating system is a vital
component of the system software in a
computer system. Application programs
require an operating system to function.
Time-sharing operating systems schedule
tasks for efficient use of the system and
may also include accounting for cost
allocation of processor time, mass
storage, printing, and other resources.

29. Application Software
Application software, also known as an application or
an app, is computer software designed to help the user to
perform specific tasks. Examples include enterprise
software, accounting software, office suites, graphics
software and media players.
Many application programs deal principally with documents.
Apps may be bundled with the computer and its system
software, or may be published separately. Some users are
satisfied with the bundled apps and need never install one.
Application software is contrasted with system
software and middleware, which manage and integrate a
computer's capabilities, but typically do not directly apply in
the performance of tasks that benefit the user. The system
software serves the application, which in turn serves the
user.

30. Compiler Software
A computer cannot understand high level languages. So
to convert high level languages into machine language, the
Computer needs a Translator. This Translator program
is called Compiler Software.
A software called the Compiler converts the Computer
language into machine language. For example there is a C
Compiler, that converts programs written in the C
language to Machine language. In order to communicate
with each other we require a Translator.