The address sequence generated by tracing a particular program executing in a pure demand paging system with $$100$$ records per page with $$1$$ free main memory frame is recorded as follows. What is the number of page faults?

$$0100, 0200, 0430, 0499, 0510, 0530, 0560, 0120, 0220, 0240, 0260, 0320, 0370 $$

Consider the following heap (Figure) in which blank regions are not in use and hatched region are in use.

The sequence of requests for blocks of size $$300, 25, 125, 50$$ can be satisfied if we use.

A memory page containing a heavily used variable that was initialized very early and is in constant use is removed when

A part of the system software, which under all circumstances must reside in the main memory is: