Personal computer video are day by day getting advance technology and some of part or types are define on it and they are:  

      1. V.G.A 

      2. S.G.A 

      3.  X.G.A

Fig: Video Standard

VGA( video Graphic Adaptor)

A graphic display system for PC are developed by IBM. VGA as becoming as a standard adaptor for PCs. VGA system provides a resolution of 720 /400 pixels is graphic mode.

SGA(Super Video Adaptor)

It is a set of graphic standard design  to offer greater resolution than VGA. There are several of SVGA is producing a different resolution.

      ·  800 by 600 pixel 

      ·  1024 by 768 pixel

      ·     1280 by 1024 pixel  

      ·   1600 by 1200 pixel

XGA(Extended Graphic Adaptor)

It is high-resolution graphic standard introduce by IBM in 1990.

There are various types of monitor and they are:-    

      1.Resolution 

      2. Interlaced or non-interlaced  

      3. Dot pitch

Fig: Characteristics Of Monitor

Resolution

Resolution means that how the pixel (dot) packed on the screen. Pixel is a single point in a graphic image. The monitor display picture by dividing the display screens into million of pixel which is arranged in row and columns. Image clear in showing 640/480 resolution that the means of screen 640 dot is column and 480 dot is row it present on screen. Text or character screen show on dot matrix for one screen it show 65 character and 25 row its will display on screen.

Interlaced or non-interlaced

Interlaced is a display technology that enable that monitor to provide more resolution in width interlacing monitor. The electron guns only half the horizontal line with each passes. It can display twice as many lines for the reference cycles.

Dot Pitch

Computer cannot operate without given by humans. It is programmed to work  effectively fast and accurately. Computer cannot think by itself and does not have common seen. It is totally dependent on human.

There are some limitation  of computer and they are:             

Fig: Limitation Of Computer

      1.   No Self-Intelligence

Computer does not have intelligence of own to complete the tasks. They given wrong output if the input given by human .

     2.   No Thinking And Decision Making Power

Computer cannot think by itself. Computer have no mind of self but it depend on the instruction of human. It cannot take decision and it can do task or instruction given by human or user.

     3.   No Felling

Lack of feeling is another limitation of computer and its cannot feel like us because computer does not have emotion like us and it can never get tired like us and keep dong work or task and computer can do very hard work or risky work because it does not have felling like user.

    4.   No Learning Power

Computer have no learning power and computer can not done any work without any instruction computer have instruction by user to do work so it can be perform by computer and computer can not learn at same time like user by giving instruction then it can be solved but cannot be learn by computer. It can do work according to instruction given.

A special type of RAM, called read-only memory (ROM), is a non-volatile memory chip, in which data is stored permanently and cannot be altered by the programmer. In fact storing data permanently into this kind of memory is called “burning in the data”, because data in such memory stored by using fuse-link. Once a fuse-link is burnt, it is permanent. The data stored in a ROM chip can only be read and used-they cannot be changed. This is the reason why it is called read –only memory (ROM).

Since ROM chips are non-volatile, the data stored inside a ROM are not lost, when the power supply is switched off, unlike the case of a volatile RAM chip. ROMs are also known as filed stores, permanent stores or dead stores.

ROMs are mainly used to store program and data, which do not change and are frequently used.

Fig: ROM

Types of Read Only Memory (ROM) – 

      ·  PROM 

      ·    EPROM

      ·  EEPROM
 

1.   PROM (Programmable read-only memory) 
 

 It can be programmed by the user. Once programmed, the data and instructions in it cannot be changed. 
 

2.   EPROM (Erasable Programmable read only memory) 

It can be reprogrammed. To erase data from it, expose it to ultraviolet light. To reprogram it, erase all the previous data. 
 

3.   EEPROM (Electrically erasable programmable read only memory) 

The data can be erased by applying an electric field, with no need for ultraviolet light. We can erase only portions of the chip. 

RAM stands for random access memory. This is where a PC stores before its processed. RAM is form of volatile memory, which means that it only holds onto data work the chip is powered and erases everything when you shut down the PC. RAM memory is measured in gigabytes(GB).

It is also called read-write memory or the main memory or the primary memory. The programs and data that the CPU requires during the execution of a program are stored in this memory. It is a volatile memory as the data lost when the power is turned off.

Fig: RAM

Two main types of RAM are:

·         Static RAM

·         Dynamic RAM

     1.   Static RAM

Static RAM is the full form of SRAM. In this type of RAM, data is stored using the state of a six transistor memory cell. Static RAM is mostly used as a cache memory for the processor (CPU).

     2.   Dynamic RAM

DRAM stands for Dynamic Random Access Memory. It is a type of RAM which allows you to stores each bit of data in a separate capacitor within a specific integrated circuit. Dynamic RAM is a standard computer memory of the many modern desktop computers.

Purpose wise computer can be classified into two types::

          ·  General Purpose Computer

          ·  Special Purpose Computer

Fig:Based Of Purpose

    1.   General Purpose Computer 

 Theses computer can store different programs and can thus be used in countless application. A General Purpose Computer  can perform any kind of jobs with equal efficiency simply by changing the application program store in main memory.

2. Special Purpose Computer  

Special Purpose Computer is the one that is designed to perform only one special task. The program or instructions set is permanently stored in such a machine. It does its single task very quickly and it cannot be used for any other purpose.

These computers are often used to perform specific function such as controlling a manufacturing process or directing communications.

The term Application refers to Software which is a set of instructions or code written in a program for executing a task or an operation in a Computer. 

Application is divided in three types of:-

        ·   Analog Computer
    · Digital Computer      
    ·  Hybrid Computer

Fig: Based Computer Application

1.Analog Computer

An analog computer or analogue computer is a type of computer that uses the continuously variable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. Analog computers can have a very wide range of complexity. Analog computers were widely used in scientific and industrial applications even after the advent of digital computers, because at the time they were typically much faster.

Fig: Analog Computer

2. Digital Computer

The definition of a digital computer is the most commonly used type of computer and is used to process information with quantities using digits, usually using the binary number system.

Example: Its only use for business for making budget to ready the budget com it be easy to do the thing of business use of digital computer.

Fig: Digital Computer

3.Hybrid Computer

Hybrid computers are computers that exhibit features of analog computers and digital computers. It is designed to include a working analog unit that is powerful for calculations, yet has a readily available digital memory.

An example of an animal hybrid is a mule. The animal is produced by a cross between a horse and a donkey. Liger, the offspring of a tiger and a lion, is another animal hybrid.

Fig: Hybrid Computer

Even though the size, shape, performance, reliability, and cost of computer have been changing over the year, the basic logic structure (based on the stored program concept), as proposed by von Neumann, has not changed.

No matter what shape and size of computer we are taking about all computer system perform the following five basic operations, for converting row input data into information.

1.   Inputting- The process of entering data and instructions into the computer system.

2.   Storing- Saving data and instruction to make them readily available for initial or additional processing, as and when required.

3.   Processing- Performance arithmetic operations (add, subtract, multiply, division, etc), or logical operation (comparisons like equal  to, less than, greater than, etc.) on data, to convert into useful information.

4.   Outputting- the process of producing useful information or results for the user, such as printed report or visual display.

5.   Controlling- Directing the manner and sequence in which all of the above operation are performed.

These five units correspond to the five basic operations, performed by computer system.

Fig: Basic Computer Organization

The function of each of these units are described below:-

Input Unit

Data and instruction must be enter the computer system, before any computation can be performed on the supplied data.

The following function are performed by an input unit:

1.    It accepts (or read) the instruction and data form the outside world.

2.    It converts these instruction and data into computer acceptable form.

3.  It supplies the converted information and data to the computer system for the further processing.

Output Unit

It links the computer with the external environment. As computers work with binary code, the result produced are also in the binary form, before supplying the result to the outside word, they must be converted to human acceptable (readable) form. this task is accomplished by unit called output interface.

Storage Unit

The data and instruction which entered into the computer system through input units, have to be stored inside the computer, before the actual processing start.

The storage unit of all computers is comprised of the following two types of storage:-

     1.    Primary storage
2.    Secondary storage

Arithmetic Logic Unit

The arithmetic logic unit of a computer system in the place, where the actual execution of the instruction take place, during the processing operation.

Control Unit

The input device know that it is time for it to feed data into the storage unit?  How does the ALU know what should be done with the data once they are received? How it is that only the final result are sent to the output device.

Central Processing Unit

The control unit and the arithmetic logic unit of a computer system are jointly known as the central processing unit. The CPU is the brain of computer system.