Basic Computer Organisation

Computer organisation is a branch of computer design that deals with description of computer features and how to interconnect them. The features includes the CPU, memory, Input/Output device.

To see other definitions or meanings of computer architecture click here.
Our discussion on this post is to understand the components of computer system and how these components interact together.

Basic Software Organisation

A program consists of two parts | instructions and data | both of which are represented by bit patterns. The instructions indicate specific operations to be performed on individual data items. The data items can be numeric or non-numeric.

It is possible to write stand-alone programs that can utilize and manage all of the system resources, so as to perform the required task. This is commonly done in controllers and embedded computers, which typically store a single program in a ROM (read-only memory), and run the same program forever. In the mid and higher end of the computer spectrum, starting with some embedded computers, a dichotomy is usually practiced, however, for a variety of reasons. Instead of writing stand-alone programs that have the ability to access and control all of the hardware resources, the access and control of many of the hardware resources (typically IO devices) are regulated through a supervisory program called the operating system. When a program needs to access a regulated hardware resource, it requests the operating system, which then provides the requested service if it is legitimate request. This dichotomy has led to the development of two major kinds of software|user programs and kernel programs.



Basic Hardware Organization:
The hardware is thus an integral part of any computer system. While nearly every class of computer hardware has its own unique features, from a functional point of view (i.e, from the point of view of what the major parts are supposed to do), the basic organization of modern computers|given in Figure below | is still very similar to that of the Analytical Engine proposed in the 19th century. This organization consists of three functionally independent parts: the CPU (central processing unit), the memory unit, and the input/output unit. The actions performed by the computer are controlled and co-ordinated by the program that is currently being executed by the CPU.



The input/output unit is a collection of diverse devices that enable the computer to communicate with the outside world. Standard input/output devices include the keyboard, the mouse, the monitor, and so on. Programs and data are brought into the computer from the external world using the input devices and their controllers. The input unit's function is to accept information from human users or other machines, through devices such as the keyboard, the mouse, the modem, and the actuators. The results of computations are sent to the outside world through the output unit. Some of the input/output devices are storage devices, such as hard disks, CD-ROMs, and tapes, which can store information for an indefinite period of time.

The memory unit stores two types of information: (i) the instructions of the program being executed, and (ii) the data for the program being executed. The CPU executes a memory-resident program by reading the program instructions and data from the memory.

Is computer architecture 1. software and hardware, 2. software or hardware OR 3. neither software nor hardware in nature? click here to see the discussion.

SHARE THIS POST WITH YOUR FRIENDS...::

Tweet