What Is The Role Of Primary Memory In The Central Processing Unit?

The primary memory which is mounted on the same board as central processing unit performs the following broad functions apart from what has been briefly described in the previous section. Data is stored in the input area, where it is held till it is required for used in processing. A part of the primary memory is used as working storage. A working store is like a sheet of paper which we usually like to keep for scribbling rough work or circulation. It holds the data being processed and the intermediate results. Output area of the storage holds the final results of processing, until they are released.

These results are stored till other information overwrites it.  Main memory also holds the source code or program. A program is an ordered set of instructions which are fetched by the control unit one at a time in order and executed. It may however be clarified here that the four general purpose areas mentioned above are not fixed by any built in boundaries. They may vary from one application to another. So in actual physical terms a certain space may store input data in one application and output results in another one and processing instructions in the third one.