computer system and it's main component .

COMPUTER SYSTEM  

                                           A computer system is made of following component :

        1.HARDWARE

        2.OPERATING SYSTEM

        3.APPLICATION PROGRAMS

        4.USERS

1.HARDWARE----------

                                       The CPU ,the memory and the I/O devices provides the basic computing resources for the system.

2. Application programs--------

                                                                  such as word processors, spreadsheet, compiler, and web browsers are used to solve user's computing problems.

3.Operating system------  An OS is a software on a computer that manages the way different program use it's hardware , and regulates the way that a user control a computer. The OS provides services such as user interface ,file and data base access.

 Main component of computer 

There are 5 major executive units of a digital computer: -

1. Central Processing Unit (CPU)
2. Visual display unit (VDU), keyboard and mouse Other input and output devices
3. Computer memory
4. Concept of hardware and software

1. Central Processing Unit (CPU)

     The CPU is the brain of a computer. Its main function is to run the program and control all other components such as memory, keyboard, pinter functions.
 It features five major building blocks, or function units, of a digital computer system. These five units are 5 basic operations, namely, input, storing, processing, outputing, and controlling data, which are completed by all computer systems. These five units are explained in the following paragraphs.

Inputing: - means data inter in computer, Which is done by the user with the help of an input device such as a keyboard.

 Storing: - It means to keep the data and instructions in the computer main memory by folding it for manipulation.
  Processing: - It means performing both arithmetic and logical operations or performing data manipulation entered in computer so that useful information can be extracted in this data.
  Outputing: - This means showing the result of information to the user either on the screen (monitor).
Or on paper (by the printer).
     Controlling: - This means directing all the above processes in coordination. This controlling is done by the control unit in the CPU.

A small computer CPU has a single micro processor. A large computer CPU has many microprocessors. This is the special function of each microprocessor.

The microprocessor consists of a control unit and an arrhythmic and logical unit ALU. While the main memory is added to the micro processor, it becomes the CPU.
   The main section of the CPU is: -
(a) Primary memory
(b) ALU
(c) Control Unit

Primary Memory
Primary memory or main memory unit is a major part of the computer or holds that data
The current that is manipulated by the CPU also keeps essential operating systems such as Microsoft Disk or MS-DOS or Windows. Since primary memory is located in the CPU itself, it is also known as internal memory or random access memory.
Arithmetic Logical Unit

Arithmetic logic unit of a computer system is where the actual operation of instructions takes place. To be more clear, all the calculations of ALU are performed and all the comparative work is done.

     Transfer to ALU whenever and as needed, data and instructions that are stored in the memory before processing are stored in the ALU generated intermediate result memory unit until it is no longer needed. Is done, where processing takes place with no processing in the memory unit.

Data from memory to ALU during primary processing
And moves back into memory again several times. After processing is complete, the final results that are stored in the memory unit or RAM are sent to the output device such as a monitor or pinter.

All ALUs are designed to perform four basic arrhythmic operations - add, subtract, multiply, and divide, in addition to performing logical operations such as Lasdain, Equal Two or Greater Than Be.

Control Unit (CU)

The unit is responsible for controlling the entire functioning of the computer. The timing and control signals generated by this unit are sent to other units for program execution and proper control. The unit also controls data transfer between memory and input / output device hubs.