The document provides information about basic computer hardware components. It begins by defining hardware as the physical parts of a computer and then lists common hardware components such as the motherboard, CPU, RAM, power supply, storage devices, and peripherals. It provides details on these "class 1", "class 2", and "class 3" components including what each component is, its function, and examples. The document also discusses different types of software, operating system features, microprocessor features, and types of application software.

1. COMPUTER BASICS
Many people believe that knowing how to
use a computer, is one of the basic skills
needed to succeed in the workplace. In order
to use the computer it is necessary to
understand how the computer works.

2. COMPUTER HARDWARE
Defination:Physical components of computer is called
hardware.
OR
Basically Computer hardware refers to the physical
aspects of the computer; the computer parts that are
tangible and can be touched.

3. COMMON HARDWARE COMPONENTS
• The Motherboard and things directly attached to it.
• Computer chassis and screen, preferly with standard
sizes (i.e. ISO A4 for notebook chassis).
• Storage Media
• Other peripherals

4. CLASS 1 COMPONENTS
CPU
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The CPU (Central Processing Unit) is the 'brain' of the computer.
It's typically a square ceramic package plugged into the
motherboard, with a large heat sink on top (and often a fan on
top of that heat sink).
All instructions the computer will process are processed by the
CPU.

5. CASE
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Most modern computers have an "ATX form factor" case in which
ATX-compatible power supplies, Mainboards and Drives can be
mounted.
The Mini-ITX is much different in important ways unlike its
relatives the Micro-ATX and the Flex-ATX. The mainboard size
can be up to 170mm x 170 mm which is smaller than the Flex and
Micro-ATX can be. Usually at less than 100 watts, the Mini-ITX
PSU is energy efficient. The Mini-ITX is also backwardcompatible with the Flex/Micro-ATX models.

6. POWER SUPPLY
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All computers have some sort of power supply. This converts the
supply voltage (AC 110 or 220V) to different voltages such as DC
5V, 12V and 3.3V. These are needed inside the computer system
by nearly every component inside the computer.
The power supply also has an exhaust fan that is responsible for
cooling the power supply, as well as providing a hot air exhaust
for the entire case. Some power supplies have two fans to promote
this effect.
It is important to buy a power supply that can accommodate all of
the components involved. Some may argue that it is the most
important part of a computer, and therefore it is worth spending
the money to get a decent one.

7. MOTHERBOARD
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The Motherboard (also called Mainboard) is a large, thin, flat,
rectangular fiberglass board (typically green) attached to the case.
The Motherboard carries the CPU, the RAM, the chipset and the
expansion slots (PCI, AGP - for graphics -, ISA, etc.).
The Motherboard also holds things like the BIOS (Basic Input
Output System) and the CMOS Battery (a coin cell that keeps an
embbeded RAM in the motherboard -often NVRAM- powered to
keep various settings in effect).

8. RAM
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Random Access Memory (RAM) is a memory that the
microprocessor uses to store data during processing.
This memory is volatile (loses its contents at power-down). When
a software application is launched, the executable program is
loaded from hard drive to the RAM.
The microprocessor supplies address into the RAM to read
instructions and data from it. RAM is needed because hard drives
are too slow to operate with the speed of a microprocessor.
Some of the types of RAM are SDRAM, DDR RAM, Rambus
RAM, SIMM, DIMM.

9. CLASS 2 COMPONENTS: STORAGE
HARD DRIVE
• A hard drive consists of one or more magnetic platters or disks
and a read arm with two electromagnetic coils for each disk.
• Each hard disk is divided into many sectors, each containing a
certain amount of data. As of now, it is the cheapest and most
common way to store a lot of data in a small space.

10. CD-ROM DRIVE
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Compact Disc Read Only Memory (CD-ROM) is a standard
format for storing a variety of data. A CD-ROM holds about 700
MB of data.
The media resembles a small, somewhat flexible plastic disc. Any
scratch or abrasion on the data side of the disc can lead to it being
unreadable.

11. FLOPPY DISK DRIVES
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8" Floppy Disk: In the late 1960s IBM invented the 8-inch floppy
disk. This was the first floppy disk design.
5.25" Floppy Disk: This disk was introduced some time later, and
was used extensively in the 1980s.
3.5" Floppy Disk: This storage medium is the most common of
those listed in this section, still in somewhat wide use today.
Floppy disks hold from 400 KB up to 1.44 MB. The most
common types found are 720 KB (low-density) and 1.44 MB
(high-density).

12. CLASS 3 COMPONENTS: PERIPHERALS
DISPLAY DEVICE
• Includes computer monitors and other display devices. CRTs and
LCDs are common.
• LCDs are a more recent development, and are gradually replacing
CRTs as they become more affordable.
• LCD's
in addition to being lighter also use less energy and
generate less heat.

13. KEYBOARD
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A keyboard is an input device which is connected to a computer
and used to type instructions or information into the computer.
Typically, a keyboard has about 100 or so keys.
Keyboards differ between languages. Most English-speaking
people use what is called a QWERTY layout.
This refers to the order of the top row of keys. Some foreign
languages (i. e. German) use QWERTZ, where the Z and Y are
switched.
Modern keyboards sometimes have extra controls such as
volume, and keys that can be programmed to bring up programs
of the user's choice.

14. MOUSE
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A user interface device that can enable different kinds of control
than a keyboard, particularly in GUIs.
It was developed at the Xerox PARC (Palo Alto Research Center)
and adopted and made popular with the Apple Mac.
Today, nearly all modern operating systems can use a mouse.
Most mice (sometimes the plural is 'mouses' to prevent confusion
with the rodent) are made from plastic, and may use a ball to track
movement, an LED light, or a laser.

15. DIFFERENT TYPES OF SOFTWARES
brief definition of each type, and the differences
between them

16. RETAIL SOFTWARE
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This type of software is sold off the shelves of retail stores. It
includes expensive packaging designed to catch the eye of
shoppers and, as such, is generally more expensive.
An advantage of retail software is that it comes with printed
manuals and installation instructions, missing in hard-copy form
from virtually every other category of software. However, when
hard-copy manuals and instructions are not required, a
downloadable version off the Internet will be less expensive, if
available.

17. OEM SOFTWARE
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OEM stands for "Original Equipment Manufacturer" and refers to
software sold in bulk to resellers, designed to be bundled with
hardware.
For example, Microsoft has contracts with various companies
including Dell Computers, Toshiba, Gateway and others.
Microsoft sells its operating systems as OEM software at a
reduced price, minus retail packaging, manuals and installation
instructions. Resellers install the operating system before systems
are sold and the OEM CD is supplied to the buyer. The "manual"
consists of the Help menu built into the software itself. OEM
software is not legal to buy unbundled from its original hardware
system.

18. SHAREWARE
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This software is downloadable from the Internet. Licenses differ,
but commonly the user is allowed to try the program for free, for a
period stipulated in the license, usually thirty days.
At the end of the trial period, the software must be purchased or
uninstalled.
Some shareware incorporates an internal clock that disables the
program after the trial period unless a serial number is supplied.
Other shareware designs continue to work with "nag" screens,
encouraging the user to purchase the program.

19. PUBLIC DOMAIN SOFTWARE
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This is free software, but unlike freeware, public domain
software does not have a specific copyright owner or license
restrictions.
It is the only software that can be legally modified by the user for
his or her own purposes.

20. TYPES OF APPLICATION SOFTWARE
Application software utilizes the capacities of a
computer directly to a dedicated task. Application
software is able to manipulate text, numbers and
graphics.

21. WORD PROCESSING SOFTWARE
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Computers have made typing papers a breeze for those of us who
do not know how to type!
We can make mistakes left and right and be able to fix them on
the computer before we print the paper.
We can save a paper as a file on a diskette and keep it for future
reference.
We can modify papers in a flash and we can even include pictures
in our papers.

22. SPREADSHEET SOFTWARE
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A spreadsheet (or spreadsheet program) is software that permits
numerical data to be used and to perform automatic calculations
on numbers contained in a table.
It is also possible to automate complex calculations by using a
large number of parameters and by creating tables called
worksheets.

23. PRESENTATION SOFTWARE
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Presentation software is becoming more commonplace for
teaching, seminars, staff meetings and other functions. The use
of data projectors means effective presentations can be prepared
with little effort. Creating a successful presentation is not hard if
a few guidelines are followed.
A presentation is a sequence of slides. A slide show is a
presentation run in front of an audience. Displayed from a
computer through a projector on a screen, a presentation would
usually be shown in full screen size. A presentation can contain
text, graphics, audio, video, and links to other programs.

24. DATABASE SOFTWARE
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A database is an organized collection of data. The data are
typically organized to model relevant aspects of reality in a way
that supports processes requiring this information. For example,
modeling the availability of rooms in hotels in a way that
supports finding a hotel with vacancies.
Database management systems (DBMSs) are specially designed
applications that interact with the user, other applications, and
the database itself to capture and analyze data.

25. FEATURES OF AN OPERATING
SYSTEM
You now have read about the various kinds of operating
systems that are part of computers ranging from a humble
mobile phone to a mighty supercomputer taking up an
entire building.

26. But they share some common features, some of which are more
important than others depending on the type of operating system
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Scheduling : The task of handling how active processes are
making efficient use of the CPU processing cycles is called
scheduling. There are many ways of doing this, which is covered
in another mini-website.
Memory Management : The operating system has to make sure
that applications are able to run in the amount of memory
available and that they do not interfere with one another. There is
a separate mini-website on this topic.

27. Allocation of resources : The operating system will provide a
working area for each user.
Keeping track of usage : The cost of using large computers is
shared amongst the users. So the operating system will have an
accounting / tracking system in place
Data and User security : Each user has to be authenticated with an
username and password (network and multi-user operating system).
Managing input / output : Data and applications are stored on
secondary storage devices such as hard disks, optical drives,
magnetic tape when not in use. The operating system has a file
management system that allows the user to organise their files, to
move, delete and copy files as they wish.

28. FEATURES OF MICROPROCESSOR
Microprocessor is the controlling unit or CPU of a
micro-computer, fabricated on a very small chip capable
or performing ALU operations and communicating with
the external word connected to it.

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Cost : The most important characteristics of a microcomputer is its
low cost. It is a well established fact that with the advancement of
technology, the cost does not increase proportionately with the
complexity.
Size : The second important features of a microprocessor is its small
size. As a result of improvement in fabrication technology, VLSI,
electronic circuitry has become so dense that a minute silicon chip can
contain hundred and thousands of transistors constituting the
microprocessor.
Power Consumption : The another important characteristics is its
low power consumption microprocessors are normally manufactured
by Metal-Oxide semiconductor technology, which has the feature of
low power consumption.

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Versatility : The versatility of a microprocessor results from its
stored program mode of operation. Keeping the same basic
hardware , a microprocessor-based system can be configured for
a number of applications simplify altering the software program.
This also makes it very flexible
Reliability: Another important property of VLSI devices which
has also been in herniated by microprocessors is extreme
reliability . It has been established that the failure rate of an IC is
fairly uniform at the package level, regardless of its complexity.