COMPUTER

INTRODUCTION TO COMPUTER

 A computer is an electronic devices, operating under the control of instructions stored in its
own memory that can accept data (input), process the data according to specified rules,
produce information (output), and store information for future use.

FACTIONALITIES OF A COMPUTER

 Any digital computer carries out five functions in gross terms:

 Takes data as input.
 Stores the data/instructions in this memory and use them when required.
 Processes the data and converts it into useful information.
 Generates the output
 Controls all the above four steps.

COMPUTER COMPONETS

o Any kind of computers consists of HARDWARE And SOFTWARE.

HARDWARE:

 Computer hardware is the collection of physical elements that constitutes a computer hardware
refers to the physical parts or component of a computer such as the monitor, mouse, keyboard,
computer data storage, hard drive disk (HDD), system unit ( graphic cards, memory, motherboard
and chips), etc. all of which are physical objects that can be touched.

Input devices
 Input devices is any peripheral (piece of computer hardware equipment to provide data and control
signals to an information processing system such as computer or other information appliance.
Input device Translate data form that humans to one that the computer can work with. Most
common are keyboard and mouse

 NOTE: The most common use keyboard is the Q W E R T Y keyboard. Generally standard
Keyboard has 104 keys.

CENTRAL PROCESSSING UNIT (CPU)

 A CPU is brain of computer. It is responsible for all functions and processes.

Regarding computing power, the CPU is the most important element of a computer system.

o The CPU is comprised of three main parts:

 Arithmetic Logic unit (ALU): Executes all arithmetic and logical operations.
Arithmetic calculations like as additions, subtraction, multiplication and division.
Logical operation like compare numbers, letters, or special characters
 CONTROL UNIT (CU): Controls and co-ordinates computer components.
1. Read the code for the next instruction to be executed.

2. Increment the program counter so it points to the next instruction.

3. Read whatever data the instruction requires from cells in memory.

4. Provide the necessary data to an ALU or register.

5. If the instruction requires an ALU or specialized hardware to complete, instruct the hardware to
perform the requested operation.

 Registers: Stores the data that is to be executed next, “very fast storage area”.

Primary Memory:-
1. RAM: Random Access Memory (RAM) is a memory scheme within the computer system
responsible for storing data on a temporary basis, so that it can be promptly accessed by the
processor as and when needed. It is volatile in nature, which means that data will be erased
once supply to the storage devices is turned off. RAM stores data randomly and processor
access these data randomly from the RAM storage .RAM is considered “random access”
because you can access any memory call directly if you know the row and column that
intersect at that cell.
2. ROM (Read Only Memory): ROM is permanent form of storage. Rom stays active regardless
of whether power supply to it is turn on or off. ROM devices do not allow data stored on
them to be modified.

Secondary Memory:-
Stores data and programs permanently: it’s returned after the power is turned off

1. Hard drive (HD): A hard disk is part of a unit, often called a “disk,” “hard drive,” or “hard
disk,” that store and provides relatively quick access to large amounts of data on an
electromagnetically charged surface.
2. Optical Disk: an optical disc drive (ODD) is a disk drive that uses laser light as part of the
process of reading or writing data to or from optical discs. Some drives can only read from
 discs, but recent drives are commonly both readers and recorders, also called burners or
writers. Compact discs, DVDs, and Blu-ray discs are common types of optical media which
can be read and recorded by such drives. Optical drive is the generic name; drives are usually
described as “CD” “DVD”, or “Blu-ray”, followed by “ drive”, “writer”, etc. There are three
main types optical media: CD, DVD and Blu-ray disc. CDs can store up to 7OO megabytes
(MB) of data and DVDs can store up to 8.4 GB of data. Blu-ray discs, which are the newest
type of optical media, can store up to 50 GB of data. This storage capacity is a clear
advantage over the floppy disk storage media (a magnetic media), which only has capacity
of 1.44 MB.

3. Flash Disk
A storage module made of flash memory chips. A Flash disks have no mechanical platters or
access arms, but the term “disk” is used because the data are accessed as if they were on a
hard drive. The disk storage structure is emulated.

Output devices
An output devices 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.

SOFTWARE:
Software is a generic term for organized collections of computer data and instructions, often
broken into two major categories: system software that provides the basic non-task-specific
functions the computer, and application software which is used by users to accomplish
specific tasks.

Software types
A. System software is responsible for controlling, integrating, and managing the individual
hardware components of a computer system so that other software and the users of the
system see it as a functional unit without having to be concerned with the low-level
details such as transferring data from memory to disk, or rendering text onto a display.
Generally, system software consists of an operating system and some fundamental
utilities such as disk formatters, file managers, display managers, text editors, user
authentication (login) and management tools, and networking and device control
software.
B. Application software is used to accomplish specific tasks other than just running them
computer system. Application software may consist of a single program, such as an
image viewer; a small collection (often called a software package) that work closely
together to accomplish a task, such as a spreadsheet or text processing system; a large
collection (often called a software suite) of related but independent programs and
packages that have a common user interface or shared data format, such as Microsoft
Office, which Consists of closely integrated word processor, spreadsheet, database, etc.;
or a software system, such as a database management system, which is a collection of
 fundamental programs that may provide some service to a variety of other independent
applications.

Unit of Measurements
Storage measurements: The basic used in computer data storage is called
a bit (binary digit). Computers use these little bits, which are composed of
ones and zeros, to do things and talk to other computers. All your files, for
instance, are kept in the computer as binary files and translated into words
and pictures by the software (which is also ones and zeros). This two number
system, is called a “binary number system” since it has only two numbers in
it. The decimal number system in contrast has ten unique digits, zero through
nine.

GUIDELINES FOR THE TEACHER

The teaching of his subject should be as practical as possible. This Kitaab has
been written to enable the child to gasp the basic Duaa’s ad to apply them to
daily living.
The questions at the end of each part may be measured in written or oral
form. These questions will ensure that the child has read with understanding.
Practical tasks appear in some parts. The simple things to be constructed by
the children will assist in making the subjects a reality. It is suggested that
once a part has been completed and the questions answered, that the teacher
help the children to make their own brief notes to emphasize the important
facts.

Apart from the practical work assigned at the end

ANOTHER PROGRAM
Computer Viruses*

Viruses: a virus is a small piece of software that piggybacks on real programs. For example.
A virus might attach itself to a program such as spreadsheet program. Each time the
spreadsheet program runs, too, and it has the chance to reduce (by attaching to other
programs) or wreak havoc.

E-mail viruses: An e-mail virus travels as an attachment to e-mail messages, and usually
replicates itself by automatically mailing itself to dozens of people in the victim’s e-mail
address book. Some e-mail viruses don’t even require a double-click – they launch when you
view the infected message in the preview pane of your e-mail software [source :Johnson:].

Trojan horses: A Trojan horse is simply a computer program. The program and security
holes to replicates itself. A copy of the worm scans the network for another machine that
has a specific security hole. It copies itself to the new machine using the security hole, and
then starts replicating from there, as well.

What are some tips to avoid virus and lessen their impact?*

 Install anti-virus software from a reputable vendor. Updates it use it regularly.

 In addition to scanning for viruses on regular basis, install an “on access” scanner
(included in most anti-virus software packages) and configure it to start each time
you start up your compute. This will protect your system by checking