All MCQs

Sequential access advances through a file in a defined order, commonly one record or byte range at a time.
It is natural for logs, streams, and tape-like processing.

A file descriptor is the process-level handle used by operations such as read, write, and close.
The kernel maps it to open-file state and the underlying object.

The create operation adds a file-system object and allocates its initial metadata entry.
Data blocks may be allocated later as content is written.

File attributes are metadata such as name, owner, size, type, timestamps, and permissions.
The other options are data contained within a file.

Mapped I/O allows the page cache pages to appear directly in the process address space.
This can reduce system-call and data-copy overhead for suitable access patterns.

Memory mapping lets ordinary loads and stores reference file-backed virtual pages.
The operating system handles page faults, caching, and eventual write-back.

During thrashing, frequent page faults cause heavy disk activity and little useful CPU execution.
Reducing multiprogramming or allocating more frames to active working sets can restore performance.

The working set estimates the process's current locality of active pages.
Keeping this set resident helps the process execute with a low page-fault rate.

Proportional allocation gives larger processes a larger share of the available frame pool.
The policy can be extended with minimums, maximums, or priority adjustments.

An instruction may span pages and access multiple operands, requiring several resident frames.
Too few frames could make correct execution or page-fault restart impossible.

Clock arranges candidate frames conceptually in a circle and scans them using a pointer.
Referenced pages receive another chance while unreferenced pages can be selected.

Second chance uses the reference bit to avoid immediately removing a recently accessed page.
Pages with no recent reference remain candidates in approximate FIFO order.