Units of a typical computer

Every computer has a certain architecture. It consists of various components. The basic function of this component is to interconnected to form a specific system. The given figure explain the basic structure of a computers.

There are three main basic units in a typical computer are as follow:-----

1. 1.Input unit.
2. 2.System unit.
3. 3.Output Unit.

Input Device

It is a kind of device that is connected to CPU(Central Processing Unit).This device is used to give all instructions and command to the computer for performing different kind of activity.There is a Control unit that take all the command and instruction from a user and send it to the CPU where it is processed as situation needs. Keyboard is the most common Input Unit. Other Input Units are as follow :-----

1. 1.Mouse
2. 2.Light Pen
3. 3.Trackball
4. 4.Disks
5. 5.Joystick
6. 6.Scanner
7. 7.Microphone

System unit

System unit is a place where all the command and data are store and processed after receiving all data from some input device. It consists of two parts are as follow:-----

1. 1.Central Processing Unit
2. 2.Memory Unit

Central Processing Unit

It is also known as CPU. It is a place where all the data and instruction are processed. For this reason it is also known as the brain and heart of a computer system. It is divided into two basic units these are:------

1. 1.Control Unit
2. 2.Logic and Arithmetic Unit

This is a very important unit as in the respect of function. It function is to control and Coordinates the total activities of all the parts and units of a computer system. There is a list of some of the function perform by Control unit are as follow------

1. 1.It brings all the instruction, Command and data from main memory.
2. 2.Interpret all type of instruction.
3. 3.It controls the movement of data from the main memory and into the main memory.
4. 4.Input and Output device is also control by Control unit.
5. 5.It is responsible for whole management of a computer system.

Logic and Arithmetic unit

All arithmetic calculation like addition , subtraction , multiplication and division are perform in this unit. It unit is also known as ALU. A typical ALU Consist of a part that is electronic circuitry and by this ALU perform all type of arithmetic calculation. For logical operation it has a Logic circuitry. It give result in two form whether TRUE or FALSE. It receives all the necessary command from the Control unit to perform all the operation that is discuss earlier.

Memory Unit

This unit is also known as storage device as name suggested. It is a place where all the data and instruction are store that are given by user side. Computer use Bytes , Bits and words to measure the memory of a computer .A Bit is represented as 0 or 1. 0 or 1 is a binary digit. A Byte is a type of sequence and is always measure in a sequence of 8 and word is measure in a sequence of 16 bits or 2 bytes.

The memory of a computer is divided into three parts are as follow:-----

1. 1.Main Memory
2. 2.Cache memory
3. 3.Secondary memory

Main memory

Main memory is a place that store all the data received through the input devices. The storage is temporary and all the data are erased when we switched off the power and that why it is known as a primary memory.

The capacity in the term of storage is measured in megabytes and gigabytes. The two most commonly primary memory is RAM Or ROM

Secondary Memory

Secondary memory is also known as a permanent memory. The capacity is very high as it store a large amount of data for a longer period of time. This memory is connected to the CPU. Magnetic material is used to made a Secondary memory. Some of the well known secondary memory are as follow -----

1. 1.Magnetic Disk
2. 2.Magnetic tape
3. 3.Magnetic Drum

Cache Memory

This type of memory is placed in between the CPU and the main memory. We can access all the data at a higher speed when we compare to a main memory. The user like us are not able to access this type of memory. During the execution of any program the data and instruction are stored in that memory.

Output Unit

This unit is used to display a result which is obtain after the execution of any program or instruction that we feed it to computer with the help of Input device. The most commonly output device is monitor. Other Output devices are as follow --------

1. 1.Printer
2. 2.Plasma Display
3. 3.Plotter
4. 4.LCD display
5. 5.Speaker
6. 6.Disks
7. 7.Printers

 

Definition of a computer.

Computer is also define as a electronic device that is used for the processing of information that we feed in a computer.Computer is a word that is formed from a latin word compute it means that to calculate.

How it process

Suppose that we feed data in a computer it accept all the data from our side and then store it in its temporary memory and then process it and give us a desire result as possible.

 

For what computer is used

1)---- Storage of large amount of data ---- computer have the ability to store a large amount of data in their permananent memory known as hard disk.All store data are remain for future until we give a delete comand to stored data.

2)---- It act as a Input and Output machine --- It function is to receive the data and instruction given by any of the user of that computer and then process it and return desire result to specified user.

3)----- Processing on data ---- It means that it process all the input data.Processing of data means performing the desired operation such as addition , subtraction , multiplication ,division and other arithmetic operations as well as logical operations on the input data.

Properties of a computer

4)----Very high speed ----- processing of data is very fast it take only a few part of second. It is capable of performing large amount of instruction per second.

5)-----Accuracy ----- It is always accurate in respect of result but you have to feed a correct input data for accurate result.Right way of processing a input data is also known as accuracy of a computer.

6)------Reliability ---- It nature is to give a consistent results every time you process a data.

7)------Versatility ----- Main role of computer is versatile.It i9s used for various purpose like calculations , processing , computer games , music , video, teaching ,etc.

8)------Diligence ----- The most important function of a computer it never tired. It can be used for longer period without any disturbance.

 

Generation of computers

The computer we use today is not develop in a day or two it takes a longer period of times in respect of years to give a computer that we usetoday.It takes generation to generation to delop.There are five generation of computer are as follows :---

These five generation of computer are further divided into two types these are:---

1)---- Non Electronic Generation

2)---- Electronic Generation

1------Non Electronic Generation is also known as the Zero(0) generation computer.

Example:---

Abacus , Differential engine.

 

2--------Electronic generation start from 1946 onward.It classified into five generations.

First Generation Computers

In this generation vaccum tube is used.In this generation there is a limitation of primary memory and use magnetic drums as in the form of secondary memory.For input and output operations it uses a punched card and a magnetic tape.

Examples :----

ENIAC , UNIVAC .

Second Generation of computers

In this generation it use a transistors.It has better primary memory as we compare to first generation of computer. It sustain a higher reliability.In this generation it use a programming language such as Pascal , AlGOL and others.

Examples :-----

IBM 1401 , GE635.

Third Generation of computers

In this generation it use a Integrated Circuits.Integrated circits contain many transistors in a single chip of silicon.It has better memory as compare to both the generation it use a semiconducductor as memory.It sustain better reliability as compare to second generation of computer.From third generation it give the facility of airline reservation , banking services as well as give weather report.

Examples:----

CYBER 175,IBM system/360.

Fourth generation of computers.

In this generation it use a LSI (large scale Integration) and VLSI(Very Large scale integration).It has larger capacity in respect of storage.From that generation a new concept was introduce that change the way of living that is networking.

Examples:----

IBM 3033 , Hp 3000.

Fifth generation of computers

This is the generation which give the definition of a super computer.In this generation it consist of a SLSI(Super large Scale Integration).From that generation it evelop all the major function of computer that we use today such as CD-Rom was introduced in that generation.

Examples:-----

Param 10000 , CRAY machine .

 

 

Introduction

MS-DOS OR DOS stand for Microsoft Disk Operating System or Disk Operating System. It is for the single user system. Not more that it is also called a  system software. It is found on a hard disk. DOS  is loaded in the Ram when we open the computer. Ram is also called a main memory of a computer.

Functions of DOS are as follows:---

1):-- It function is to organization of hardware components with software.

2):--It function is to load and  execute  a program that is done by user on that computer.

3):-- It function is to organize the file on the disk in a orderly way.

Booting

Booting is also known as the process of loading DOS into the main memory that is Ram. When we start a computer and try to boot it from the hard disk. The display of the computer display different messages such as follow  below : ---

C:\>  ___________________Cursor.

C:\>  ___________________Current Disk.

C:\>  ___________________Root Directories.

C:\>  ___________________Prompt required to show the directory.

Directory

Every Directory holds a files and subdirectories. In each of the disk there is a at least one directory. This directory is known as the main directory or the root directory. The directory name must contain a 1-8 charaters.

Examples:----

1. 1.Com
2. 2.The
3. 3.Sit

You get a directory name that has some meaning.

File

Files hold a different type of program and different type of data. Each of the file is known by his file name. These type of file are maintain by using of various directory.

File Name

The name of the file must contain a 1 to 8  character in nature. It is represented by using a 1 to 3 character.File name is mandatory where as the extension name is not much mandatory.if we want to give extension name we must use a dot.

Such as :---

Chandan.abc

Chandan is a file name and abc is a extension name whereas file name and extension name is separated by a dot.

Maths

This is a type of a file name without using the extension name.

 

Some of the important DOS commands:---

1):---C:\> dir

This type of command is used to show all the names of  files and a subdirectories. It show the following type of things are as follow:--

1. 1.Name of File
2. 2.Extension Name
3. 3.Number of the Bytes
4. 4.It gives the Right Date and time of the creation of the Files or Directiories.

When a directory contain a large number of files and subdirectories then it is good to scroll over your computer screen for a better reading.

2):-- C:\>  dir/p

This is a type of command which is used to give page wise display of a files and a subdirectories in a specific directory. It show the following type of things are as follow:--

1. 1.Name of File
2. 2.Extension Name
3. 3.Number of the Bytes
4. 4.It gives the Right Date and time of the creation of the Files or Directiories.

We use any of the key while we try to move from one page to another.

C:\>  dir /w

This type of command is used to show 5 names in one line of all the files and subdirectories present    in a specified directory. It shows following are as follow:--

1. 1.Name of File
2. 2.Extension Name

C:\>  dir /ad

It is used to display all the name of the subdirectories contained in a specific directory.

C:\>  ver

This command is used to see a version of the MS-DOS that you use on your system.

D (root directory)  ----------------- Chandan (directory) ------------------physic(sub-directories)  dl.bcd                                                                         

D (root directory)  ----------------- Chandan (directory) ------------------math(sub-directories)   mark.bcd

D is a type of root directory.

Chandan is a sub-directory of a root directory of D and root directory for physic and math.

Physic and math is a sub-directories of a chandan directory and a sub-directories of a root directory of D.

dl.bcd and mark.bcd is a file present in the specific sub-directories physic and math.

How to make a directory:----

C:\>  md  chnadan

Command which is used to make a directory is md.

Chandan is used as name of the directory.

How to delete a file:---

C:\chandan\physic> del dl.bcd

                 Or

C:\chandan\math> erase mark.bcd

In this section we use a del or erase command to delete a file from directory or sub-directories.

How to remove a directory:---

C:\chandan\physic>  cd   ------------------------- 1^st process(It remove file and sub directories)           

C:\chandan> rd physic    -------------------------2^nd process(It remove directory).

We use rd command to remove a directory.To remove the directory first of all we have to remove all the sub directories  and file that is present in that directory after that we are able to remove a directory.

How to remove all the file that is present in a directory physic :-----

C:\chandan>  cd physic

C:\chandan\ physic>

C:\chandan\ physic>  del**

How to remove a directory physic and math :-----

C:\chandan\physic>  cd………

C:\chandan> rd physic

C:\chandan>  cd………

C:\>  rd  chandan

C:\>

By apply this process you are able to delete all the directory.

How to move from a C drive to other drive on your computer:---

C:\> a :

We can use a command a: to move from C drive to other drive.

a : \ >

It indicate that we are in a other drive.

We use the reverse case while you want to move from other drive to a C drive.

a:\>  c:

Here we use a c: command which is used to move from other drive to C drive.

By clicking on the icon such as MS_DOS prompt we can go to DOS prompt.It will appear just like this as below:-----

C:\>

There are some command use in C- programming to make save , compile , run ,and see a result of you programme:------

1. 1.F2 -  This key is used to save a program written by you.
2. 2.F3 -  This key is used to open a program that is save by use in your previous session.
3. 3.F9 - This key is used compile your program written by you.
4. 4.Ctrl F9 - This key is used to run the program written by you.
5. 5.Alt F5 – This key is used to see the result of your executed program.
6. 6.Alt X – This key is use to came out from the TC editor section.

Windows operating system

It is also known as the GUI (graphical user interface).This type of operating system is a user friendly operating system. It is different from the DOS operating system because there is no need to remember any kind of command to run your computer because all the thing will be display on the computer screen itself that why is known as user friendly operating system. Till now there are various kinds of windows operating system release. Today we use a window 7 operating system. It does not develop to a that much it takes a lots of period and many form of window operating system pass in that period.

Different components of the windows operating system are as follows:--------

In this section we take a simple window operating system for a example.

TITLE BAR

The top most part of the any windows operating system is called a title bar as indicate above.The following thing it can display these are:----

1. 1.Window Name
2. 2.Minimize button , maximize button and Close button as show below figure.These all buttons are on the right hand side of windows.

1. Minimize button is used to minimize the window which you open.

2. Maximize button is used to maximize the minimize window.

3. The close button is used to completely close the window.

MENU BAR

Menu bar is a part of the window display just below the title bar.It contain a lot of option such as FILE , Edit , View , Insert , Format , Help , Tools , Window. For using each of the option you have to pull down each of the option down ward.

STANDARD TOOL BAR

This option is display below the menu bar. It contain a number of icons s in figure.When you create any document this option play very important role without this you are not able to make a document.

FORMATTING TOOL BAR

This option is display just below the standard tool bar and this portion contain a lots of command for your document in the form of a buttons.

Suppose that there is no tool for formatting and even there is not a standard tool bar you have to choose a view option from the menu command and dragging down ward a menu is open on the side of the window use that as a standard and formatting tool bar.

STATUS BAR

It function is to display the total number of item are present in the windows.It also display the total memory  are taken by that item.

MOUSE AND KEYBOARD

When you work on the window then you need a mouse and keyboard to give a instruction to the window. Among the both of the mouse and keyboard mouse is better for windows operating system.

Basic function of mouse are as follow:-----

1. 1.It move on the pad and as we move it also move on the computer screen.
2. 2.When the mouse curser is pointing on any of the icon we click it to open an application.
3. 3.If you are in a hurry then you press right mouse twice to immediate open an application or folder.

 

INTRODUCTION ­

One day  when you go to market and you find a lacking of cash in your pocket,What you do in thatsuitation.The only way is to go to ATM(Automated teller machine)  take your bank atm card and insert your card into the card reader of atm machine and by following some certain rules you got a cash in your pocket and you continue your shopping.

Lets comes to know that how this ATM  machine works and make you ready for shopping without lacking of cash.

 

Difference between ATM card and check card

­ ­

­Today most of the banks start giving a check card which is also known as credit debit card to their customers. This check card are different from the ATM cards.

First of all the  check cards are known as debit cards because by seeing the process of work done by debit card.This check card deducts cash from your savings bank account for your purchase done in a store or other place while ATM card gives you a cash for your purchasing done by you.The second difference is that ATM card is only use in a ATM machine and very fews store too but check card are use in all most of all the shop where credit card are accepted.­

However some hotel and and some car services centre they uses a credit card only because the use of the credit card are easy and free from the risk when we compare to the check card or the debit card.

 

How Do ATMs Work

 

 

ATM is a type of a data terminal.It has two input and four output devices. When we connect ATM then it communicate through a host processor. The host processor is a type of a  analogous to an ISP or internet service provider that is a path through which all the ATM of different bank networks become available to the bank customer who have ATM card.

Today most of the  host processors either support leased-line or dial-up machines.That connect directly to the host processor with the help of a  four-wire, point-to-point, dedicated  telephone line is known as a leased-line machine whereas those connect to the host processor with the help of normal phone line with the help of ISP is known as Dial-up Machine.

Some of the independent service provider or a financial institution or a bank are own a host processor.

Parts of the Machine

As we know that a ATM machine has a two input devices these are card reader and a keypad:-

• Card reader –The function of the card reader is to captures your account information that is stored on the back side of your ATM that is a magnetic strip.Now the host processor uses this information to  complete your transcation to the bank that you associate.
• Keypad – The function of the keypad is that it can be uses to select type of transaction,amount of your cash and it also used to type your personal pin on the ATM machine screen.

 

            There are four type of output devices these are speaker, display Screen, receipt printer and cash dispenser.

• Speaker – It function is to provides the customer with a audio feedback when a customer press a key.
• Display screen – It function is to give the direction  to the customer that include stet by step process of the transaction. Leased-line machines use a monochrome or the color CRT display whereas Dial-up machines use a monochrome or the color LCD display.
• Receipt printer – It function is to provides the customers a paper receipt of the transaction made by him.
• Cash dispenser – It function is to give a cash after transaction is complete.This is also known as the heart of an ATM.

Sensing of Bills

­ In a cash dispenser there is a mechanism that is known as cash-dispensing mechanism.It has an electric eye that function is to count each bill. After the counting of the bill all the information of a particular transaction is recorded in a journal. Now the  information that is stored in a journal is printed out by a receipt printer and the copy of that transaction is stored in a hard disc of a machine for a two years.When the customer having any dispute about any of the transaction he or she take out the printout and then contact to the host processor.The host processor is responsible for resolving all the dispute that is created during the transaction.

The cash-dispensing mechanism has a sensor along with the electric eye that count the bills it function is to evaluates the thickness of each bill. In a case of two bill struck each other and try to come out then it make a direction of that two bill that stuck each other to the reject bin.

Machine also record the numbers of the reject bill for future.When the ratio is high it indicate that there is a problem in a dispenser mechanism.

 

Settlement Funds

­When a customer  go to the ATM and perform ATM tra­nsaction, Then there is a need of specific information with the help of card reader and the keypad. Now the ATM  carry this information to the host processor, which carry the transaction request to the customer’s bank. When we request a cash then the host processor makes an   electronic fund transfer that   take place from the customer's bank account and carry to  the host processor's account. When the funds are successfully transfer to the host processor's bank account then the host   processor sends an approval code that help to give cash to the customer through the cash dispenser. That why when you request for a cash then  the money moves electronically from your bank account to the host's account and you got a cash in your hand.

 

ATM Security

­ ­For security of your ATM you must keep your personal identification number (PIN) and other information secure and safe.There are lot of thing keep in your mind while you go to ATM machine.

Step for keeping your pin secret:-

• Do not write your ATM PIN on any of  the  paper. Try to keep your ATM pin in your mind .IF necessary keep your pin in a safe place not in your wallet or purse.
• Try to create your pin such that you may easily remember. Always change you ATM pin with a regular interval.
• Does not give a telephone number and birth date and house number as your ATM pin.

Tip for safe usage of ATM:-

• First of all keep your ATM in a purse and wallets and try to keep away from scratch  and bent.
• Not to take out your ATM card   outside the ATM   room. You may attach by other person too .
• You always try to Stand directly in front of the ATM keypad when you are typing your personal PIN.
• When your  transaction is complete you must take your receipt,  your card and money.
• If you come ATM by your bike or car you keep this closer to the ATM so that you easily go from there in a safe way.
• Do not leave your car running while using a walk-up ATM. Take your keys with you and lock the doors before your transaction.
• If you find something wrong in a ATM machine then you cancel your transaction and go to the bank and ask this for your problem to the bank authority.