Cpu components.

CPU COMPONENTS

The CPU is the intelligence of the machine but it needs a pre-written program to create, use and modify the data. If the computer needs to compare two numbers, or add two numbers, this is carried out inside the CPU and the numbers have to be fetched into the CPU from the computer’s memory chip. The three main components of CPU are: Arithmetic logic Unit (ALU), Bus Interface unit, and the Control Bus.

Arithmetic Logic Unit (ALU) carries out all the calculations and decision making tasks. The ALU uses devices called gates that receive one or more inputs and based up what function they are designed to perform, outputs a result. The basic operations of an ALU include adding and subtracting binary values as well as performing logical operations such as AND, NOT, OR AND XOR.

The Bus Interface Unit takes the data to and from the CPU which is held inside internal registers (small memory stores) along the external Data Bus to read and write memory and devices. The Data Bus carries information in both directions. The Bus Interface Unit also places the required location addresses on the Address Bus, so that the required devices can be accessed for reading or writing.

The Control Bus is the physical connection that carries control information between the CPU and other devices within the computer. It decodes all program instructions and dictates all the CPU’s control and timing mechanisms. It sends out the read and write signals on the Control Bus.

SYSTEM SOFTWARE

A computer system is not complete without system software. For a computer to perform any tasks, both software and hardware are equally important. System software gives life to hardware. System softwares are the files and programs that make up a computer’s operating system. It includes libraries of functions, system services, driver for hardwares, system preferences, and other configuration files. System software comprises of Assembler, Debugger, Compilers, Operating System, File management tools etc. The system software is installed on the computer when the operating system is installed. It can also be updated by running programs such as “windows update”.

The system software is also called “low-level” software as it runs at the most basic level of the computer. It generates the user interface and allows the operating system to interact with the hardware; however system software is not meant to be run by the end user like application programs. Application programs such as web browser, or Microsoft word is often used by the end user whereas the end user does not use an assembler program unless he/she is a computer programmer. The system software runs in the background and thus the user does not have to worry about what the system software is doing.

CONCLUSION

In the report, the basic structure of a computer system was described with diagram. Different components such as CPU, memory, BUS, input/output devices that form a computer system were identified and explained. General ideas about Logic gates were given and different number systems used by computers to represent data were also described. As the CPU is the main part of a computer system, it was further looked into and Arithmetic Logic Unit, Control Bus and Bus interface Unit were discussed. Different types of memory and their uses were explained and the importance of the system software was discussed finally.