All MCQs

The valid-invalid mechanism lets hardware reject references outside the process's permitted pages.
In virtual-memory systems, related state can also indicate whether a legal page is resident.

A process size is rarely an exact multiple of the page size.
The remaining bytes in its final frame are allocated but unused.

Paging can place pages in any free frames, so one large contiguous physical hole is unnecessary.
Some internal fragmentation may still occur in the final page of a process.

A power-of-two page size lets hardware divide an address by selecting high and low bit ranges.
No arithmetic division is needed to identify the page number and offset.

The page number selects a page-table entry, and the offset selects a byte within that page.
The physical address combines the resulting frame number with the unchanged offset.

A page table provides the translation information required for paged address spaces.
Each process normally has its own mapping because its virtual address space is independent.

Physical memory is divided into frames of the same size as logical pages.
The page table records which frame contains each page.

Paging divides logical memory into equal-sized pages.
Pages can be placed into any available physical frames.

The buddy system organizes blocks by powers of two for fast splitting and coalescing.
Two free buddies of the same size can merge into their parent block.

Compaction relocates processes so separated free areas become one larger hole.
It requires dynamic relocation support and can be expensive.

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.

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