computer book

PROCESSING HARDWARE

2011-08-14T05:30:00.000-07:00

PROCESSING HARDWARE:

Processing hardware comprises the electronic inside the cabinet of the computer itself. Two components handle processing in a computer. the central processing unit and the memory. Both are located on the computer's main system board, or motherboard.

CENTRAL PROCESSING UNIT (CPU)

The central processing unit (CPU) executes program instruction.you can think of it as the computer's brain. In a microcomputer, the entire CPU is contained on a tiny chip called a microprocessor, which is no larger than your smallest fingernail. the chip n9is mounted on a piece of plastic with metal leads attached to it. this microprocessor defines type and overall characteristics of a computer. The microprocessor may have a number like 8088,80286,80386,80486,80586,80686 etc. Here first microprocessor number represents an IBM XT computer, while others called IBM AT computers. some companies design many other types of microprocessor with different microprocessor numbers.
The CPU has two main components (Fig.):
1.The control unit
2.The arithmetic/logic unit

POINTING INPUT DEVICES (B PART)

2011-08-13T11:54:00.000-07:00

TOUCHSCREEN:

A touch screen is a special type of computer display screen that allows commands to be entered by the user's touching by the screen see figure.Labelled boxes on the screen display choices available to the user.Touch screens are generally used in the locations such as airports and hotels to display certain type of menu.
LIGHT PEN:

The light pen consists of a highest-sensitive pen-like device that enters commands into a special display screen when the users touches the screen with the pen (see figure).Light pens are frequently used by illustrators,graphic designers,and drafting engineers.

DIGITISING TABLET:

A digitising tablet,or digitisers,consists of a flat drawing surface and a pointing tool,which creates images that are converted to computers-usable from (see figure).The tablet,which is covered by a grid of tiny wires,is connected by cable to the computers.Drawing are entered into the tablet,using the special pen-like device,and are displayed on the computer screen.Later the drawing can be printed out.Digitising tablets are used in air craft design and computers-chip design.

PEN-BASED COMPUTERS:

Pen -based computers allow users to write on the screen of the computer,which then interprets the hand-writing and displays the result on the screen in printed from (see figure).Users can edit what they have entered and give commands by circling words,checking boxes,and using symbols developed by the manufacturer.

POINTING INPUT DEVICES (A PART)

2011-08-12T08:39:00.000-07:00

The kind of direct-entry input devices known as pointing devices are easy to use because there is nothing easier than pointing.Pointing devices are used in menu driven programs--that is,program that offer varying levels of menus,or choices displayed in lists,to the user(see figure)
MOUSE:

A mouse is a small,hand-operated device that is connected by cable to the computer and that moves the cursor on the display screen (see Fig.).As you move the mouse around on the desktop, the cursor moves across the screen.when the cursor reaches your desired location,you may push a button on the mouse to signal a command to the computer.
The mouse can also be used like a pen or a paintbrush to draw figures and create patterns directly on the video display screen.A sophisticated mouse enables user to generate very complex and precise images.The keyboard,however,is still used to type in characters and to issue some commands,depending on the software.
Trackball:

A trackball is a pointing device resembling a mouse but is stationary and is guided by the figure instead of rolled on the desktop .Some computer have built_in trackballs.Trackballs may also appears on the side of a computer keyboard. These devices are use full in situations where there is no room to move a mouse,as in the aeroplane,s cockpit.
JOYSTICK:

A joysticks is used to play game on computer.It is a device that controls the movement of certain object on the screen see figure. the button on the joysticks allow the user to perform different action depending on the nature of the programs.

KEYBOARD INPUT DEVICE

2011-08-12T06:02:00.000-07:00

The most common means by which you will input data is through a keyboard.
KEYBOARDS

A keyboard is an input device that looks like a typewriter keyboards but has associational keys for specific purposes.Amount IBM-compatible computer,the most common word keyboards layout is the IBM enhanced keyboards as shown in figure.It has 101keys arranged in the following five groups.

Character keys
Function keys
Special-purpose keys
Numeric keys
Cursor-movement keys

CHARACTER KEYS:

These character keys are used to type in text (letters and numbers, such as A,B,C, D AND 1,2,3,4)

FUNCTION KEYS:
The functional key are those labelled F1,F2,F3 and so on,and are used to issue frequently used commands .most keyboards have 10 to 12 function keys.
SPECIAL-PURPOSE KEYS:
Special purpose keys are used to help enter and edit data and execute commands.These are

ENTER------execute command
Ctrl,Alt,Shift----------modifiers
Del and Ins-----------editing
Caps lock-------upper-case

NUMERIC KEYS:

The numeric keys ,or numeric keypad, which is usually located on the right side of the keyboard, is the part that looks like an adding machine, with 0 through 1 keys and the mathematical operations (*,+,* and /)
CURSOR-MOVEMENT KEYS:
The cursor is the blinking symbol on the screen that shows where data may be entered next.The cursor-movement keys,which are represented by directional arrows, move the cursor around the screen.

INPUT DEVICES

2011-08-11T06:50:00.000-07:00

Input and output devices are essentially converters.People understand letters,numbers,and punctuation marks.However,computer can understand only the machine language of binary 0s and 1s.Input devices convert what people understand to what computers understand.Output devices do the reverse:they convert machine language to languages people can comprehend.

Input devices consist of devices for entering data into a computer system in a form that can be processed by the computer.There are two kinds of input hardware.They are:

Keyboard devices
Non-keyboard,or direct-entry,devices

In keyboard entry,data is input to the computer through a keyboard.this look like a typewriter keyboard but has additional keys.in this method ,the user reads from an original document ---called the source document ---and copies that document by typing on the keyboard.in direct entry,data is made into machine-processable from as it is entered into the computer;no keyboard is used.

LOOKING INSIDE THE MACHINE

2011-08-11T06:17:00.000-07:00

The computer itself-the hardware has many parts.Figures show the part of a typical personal computer system.In additional to the CPU,RAM,ROM,and associated control circuits that reside in the microcomputer it self,other components,called peripheral device,are need to make a complete micro computer system.

Peripheral equipment includes all input,output,and secondary storage device.In the case of personal computer ,some of the input,output ans storage devices are built into the same physical unit.In many personal computers,the CPU and disk drive are all contained in the same housing,the keyboard and screen are separate.
A typical digital computer system has four basic functional elements:

Input
Processing
Output
Storage

these element in detail in new post

PARTS OF COMPUTER SYSTEM

2011-08-10T22:28:00.000-07:00

When we think of a computer system,perhaps we thinks of just the equipment itself.However ,there is more to a computer system than that.A complete computer system consists of five parts:

Hardware
Software
Data
Procedure
people

HARDWARE

All physical components are called hardware.In other words,hardware is any part of the computer you can teach .Hardware consists of interconnected electronic device.Such as keyboard,mouse,monitor,printer etc.That you can use the computer operation,input and output.

2. SOFTWARE

All computer program are called software.software is the set of instruction(also called a program) that tell the computer how to perform a task.In other words, software tells the computer what to do.

3.DATA

Data consist of raw facts and figures, which their computer stores and reads in the form of number. The computer processed data according to the instruction contained in the software.After data is processed through the computer,it is called information.A use full model to describe the relationship between data and information is called data processing cycle.It shows that dta goes into a process and information is then output as:
INPUT------->PROCESSING-------->OUTPUT INFORMATION

4.PROCEDURES

Producer are the steps that you must follow to accomplish a specific computer -task.Manuals containing rules and guidelines to follow data are available.These manuals may be written by computer specialists for a particular organisation. Usually,However,software and hardware manufactures provide manuals with their product.

5.PEOPLE

People are the computer operators,also knows as user(or sometimes end user).People operate the hardware, crate the software,put data into the system ,and use the information that comes out of it.

COMPUTER SYSTEM

2011-08-10T20:22:00.000-07:00

A system is group of integrated part that have the common purpose of achieving some objective(s).So, the following three characteristics are key to a system:
characteristics are given below.

A system has more than one element.
All the element of a system are logically related.
All the element of a system are controlled in such away that the system goal is achieved.

Since a computer is made up integrated components (input and output devices, storage,CPU) that work together to perform the steps called for in the program beings executed, it is system .The input or output units cannot function until they receive signals from the CPU ,Similarly,the storage unit or the CPU alone is of no use.So the usefulness of the each unit depends on other units and can be realized only when all units are put together (integrated) to form a system.

CHARACTERISTICS OF A COMPUTER

2011-08-08T22:26:00.000-07:00

Speed
Accuracy
Diligence
Versatility
Power of remembering
No I.Q
No feeling

SPEED: A computer is a very fast device. it can perform in a few second the amount of work that a human being can do in an entire year.To put in a different manners, a computer does in one minute what would take a man his entire life time.

ACCURACY: The accuracy of a computer is consistently high and the degree of accuracy of a particular depend upon its design.But for a particular computer, each and every calculation is performed with the same accuracy.Errors can occur in a computer, but these are mainly due to human rather than technological weaknesses,that is,due to imprecise thinking by the program or due to inaccurate date.

DILIGENCE:Unlike human beings, a computer is free monotony,tiredness,lack of concentration, etc..,and hence can work for hours together without creating any error and without slackness.Due to this property ,computers obviously score over human beings in doing routine types of jobs which require great accuracy .If ten million calculations have to be preformed, a computer will perform the ten millions calculation with exactly the same accuracy and speed as the first one.

VERSATILITY:Versatility is one of the most wonderful things about the computer. One movement,it is preparing the result of particular examination,the next moment it is busy preparing electricity bills,and in between,it may be helping an office secretary to send a fax in second.All that is required to change its talent is to insert a new program into it.Briefly,a computer is capable of performing almost any task provided that task can be reduced to a series of logical steps.

POWER OF REMEMBERING:As a human being acquires new knowledge,the brain subconsciously sleets what it feels to be important and worth retaining in its memory,and relegates unimportant details to the back of the mind or just forget them.With computer,this is not the cause.A computer can store and recall any amount of information because of its secondary storage capability.Every piece of information can be retained as long as desired by the user and can be recalled as and when required Every after several years,the information recalled will be as accurate as on the day when it was fed to the computer.A computer forget or looses certain information only when its is asked to do so.So it is entirely up to the user to make a computer retain or forget a particular information.

NO I.Q:A computer is not a magical device.It can only perforation tasks that a human beings can.The different is that the performs these task with unthinkable speed and accuracy.It possesses no intelligence of its own.Its I.Q (intelligence quotient) is zero, at least till today.It has to be told what to do and in what sequence.Hence, only the user can determine what tasks a computer will perform.A computer cannot take its its own decision in this regard.

NO FEELING:Computer do not have emotions .they they have no felling because they are machine.Although men have succeeded in building a memory for the computer,but no computer possesses the equivalent of a human heart and soul.Based on our feeling,taste,knowledge,and experience,we often make certain judgements in our daily life.But computers cannot make such judgements on their own.Their judgement is based on the instructions given to them in the form of programs that are written by us. they are only as good as man makes and uses them.

COMPUTER SCIENCE AND INFORMATION TECHNOLOGY

2011-08-06T09:12:00.000-07:00

Computer science is the best of computers namely, their design (architecture) and their uses for computations, data processing,and systems control.Computer science includes engineering activities such as the design of computer and of the hardware and software that make up computer systems.Since computer system are often too large and complicated to allow one to predict the failure or success of a design without testing it, experiment is incorporated into their development cycle.computer is generally consider discipline separate from computer engineering,although the two disciplines overlap extensively in the area of computer architecture,which is the design (and study) of computer systems.
The major sub -disciplines of computer science have traditionally been:

architecture (including all levels of hardware design, as well as the integration of hardware and software components to from computer system).
software (that program ,or sets of instruction ,that tell a computer how to carry our tasks).The field is subdivided into software engineering ,programming languages ,operating system ,information systems of database, artificial intelligence,and computer graphic.
theory,which includes computational methods and numerical analysis on the one hand and the data structure and algorithms on the other.

Information teratology is a contemporary term that describes the combination of computer technology (hardware and software) with telecommunication technology(data ,images, and voice networks).The arrival of information technology is having powerful consequences the most notable being the gradual fusion of several important industries in a phenomenon the has been called technology convergence.
When information technology is used ,the user is responsible for the efficient capture of data from its organization,s source, the flow of data that data to the computer,the processing and storage of that data by the computer ,and the flow of useful and timely information back to the organization and its people. In short information technology is a term that refers to the efficient usage of information. in a domain of interest.

BASIC CONCEPTS OF COMPUTER

2011-08-02T08:00:00.000-07:00

The term computer is derived from the word "compute" which means to calculate.So a computer is normally considered to be a calculating device that can perform arithmetic operations at enormous speed.

In fact, the original objective for inventing the computer was to create a fast calculating machine. But more than 80% of the work done by computer today is of non-mathematical or non numerical nature.Hence,to define a computer merely as calculating device is to ignore over 80% of its work.

More accurately,a computer may be defined as a machine that receives data as input, processes that data according to a prescribed sequence of instruction and produces desired output.