Operating System MCQs

Variable partitioning allocates contiguous holes sized according to arriving process needs.
As processes enter and leave, external fragmentation can develop.

First fit scans memory and uses the earliest hole that satisfies the request.
It often performs faster than strategies that search all holes.

Best fit searches for the tightest hole that can contain the process.
It may leave many very small unusable fragments.

Worst fit uses the largest hole in an attempt to leave a sizable remainder.
It requires finding the largest suitable free region.

External fragmentation wastes memory between allocated regions rather than inside them.
The total free space may be sufficient even though it is not contiguous.

Internal fragmentation occurs within a partition, page, or allocation unit assigned to a process.
The leftover space cannot be used by another allocation while the block remains assigned.

Dynamic linking uses a small runtime stub to locate and bind a shared library routine when needed.
It supports library sharing and updates without embedding every routine in each executable.

Swapping frees main memory by transferring inactive process contents to a backing store.
The process can later be brought back into memory and resumed.

Roll out, roll in uses swapping to make memory available for a more urgent process.
The lower-priority process is restored when sufficient memory becomes available.

Load-time binding postpones absolute address selection until the loader places the program in memory.
After loading, the process normally remains at that chosen location.

Execution-time binding translates addresses dynamically during every memory reference.
Hardware support such as an MMU allows the process to relocate while executing.

The memory-management unit performs hardware-supported address translation and protection checks.
It sits between processor-generated addresses and physical memory.