Protection Of Memory

Q1. Explain Protection of Memory.

Ans. As computer systems have become more sophisticated and pervasive in their applications, the need to protect their integrity has also grown. Protection was originally conceived as an adjunct to multiprogramming operating systems, so that untrustworthy users might safely share a common logical name space, such as a directory of files, or share a common physical name space, such as memory. Modern protection concepts have evolved to increase the reliability of any complex system that makes use of shared resources.

We need to provide protection for several reasons. The most obvious is the need to prevent mischievous, intentional violation, of an access restriction by user.

Logical Address Space

Figure: Logical Address Space

Segment no. Limit Base
0 1000 1400
1 400 6300
2 400 4300
3 1100 3200
4 1000 4700

Figure: Segment Table

Physical Memory

Figure: Physical Memory

 

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