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Unformatted text preview: space for storing data and instructions, space for intermediate results, and also
space for the final results.
In short, the specific functions of the storage unit are to hold (store):
1. All the data to be processed and the instructions required for processing (received
from input devices).
2. Intermediate results of processing.
3. Final results of processing before these results are released to an output device.
The storage unit of all computers is comprised of the following two types of storage:
1. Primary storage. The primary storage, also known as main memory, is used to hold
pieces of program instructions and data, intermediate results of processing, and recently produced results of processing of the job(s) that the computer system is currently working
on. These pieces of information are represented electronically in the main memory chip's
circuitry, and while it remains in the main memory, the central processing unit can access
it directly at a very fast speed. However, the primary storage can hold information only
while the computer system is on. As soon as the computer system is switched off or reset,
the information held in the primary storage disappears. Additionally, the primary storage
normally has limited storage capacity because it is very expensive. The primary storage
of modern computer systems is made up of semiconductor devices.
2. Secondary storage. The secondary storage, also known as auxiliary storage, is used to
take care of the limitations of the primary storage. That is, it is used to supplement the
limited storage capacity and the volatile characteristic of primary storage. This is because
secondary storage is much cheaper than primary storage and it can retain information
even when the computer system is switched off or reset. The secondary storage is
normally used to hold the program instructions, data, and information of those jobs on
which the computer system is not working on currently, but needs to hold them for
processing at a later time. The most commonly used secondary storage medium is the
ARITHMETIC LOGIC UNIT
The arithmetic logic unit (ALU) of a computer s...
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This document was uploaded on 04/07/2014.
- Spring '14