Operating System MCQs

SSTF attempts to reduce immediate seek distance by choosing the nearest request.
Requests far from a frequently busy region can suffer starvation.

Contiguous allocation records a starting block and length for a run of adjacent blocks.
It provides fast sequential and direct access but makes growth and external fragmentation difficult.

Linked allocation forms a chain of blocks that may be scattered across the disk.
It avoids external fragmentation but provides poor direct access and pointer overhead.

A single-level directory places every file in one directory and requires globally unique names.
It becomes inconvenient as the number of users and files grows.

A two-level structure associates a user file directory with each account under a master directory.
Different users can therefore use the same file name without conflict.

A tree directory organizes files hierarchically through parent and child directories.
Absolute and relative pathnames can identify objects at different levels.

An acyclic graph allows an object to have multiple directory references without creating recursive cycles.
Reference counts or similar mechanisms help manage deletion of shared objects.

A symbolic link stores a textual path that the file system resolves when accessed.
It can cross file systems but may become dangling if the target is removed.

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

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.

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.

Direct access computes or specifies the desired block or record position independently of previous accesses.
It is well suited to disk-based databases and large fixed-record files.