Computer Operating System Questions and Answers

Answer: B

Correct answer: FORMAT A: /Q

/Q performs a quick format: it rewrites the file allocation table and root directory but does not re-create the sector structure or scan for bad sectors. It is fast, and it works only on a disk that has already been formatted once.

Answer: A

Correct answer: XCOPY/D : date

XCOPY with the /D:date switch copies only those files whose modification date is on or after the date given, so an incremental copy can be taken without listing the files by hand. Plain COPY has no such switch.

Answer: D

Correct answer: hashing

Hashing computes a storage address directly from the record’s key, so a record can be reached in a single access without consulting an index. Its cost is collisions, when two keys hash to the same address, which must be resolved by chaining or by probing.

Answer: D

Correct answer: all of the above

Sound evaluation draws on all three: other users report how the package behaves in daily work, magazines compare it against its rivals, and an objective review tests it against stated criteria. Each covers what the others miss, so together they give a fuller picture than any one alone.

Answer: D

Correct answer: an interpreter

An interpreter reads a high-level program one statement at a time, works out what it means, and carries it out immediately, without producing a machine-code file. That makes it slower than compiled code but far quicker to test, since a changed line can be run at once.

Answer: C

Correct answer: SCANDISK

SCANDISK checks both the logical structure of a drive - the file allocation table, directory entries, lost clusters and cross-linked files - and, with a surface scan, the physical media, and it works on DoubleSpace compressed drives as well as ordinary ones. DEFRAG only rearranges files.

Answer: B

Correct answer: Shareware

Shareware is distributed freely so that it can be tried, on the understanding that a fee is paid if it is kept and used. It remains copyrighted - which distinguishes it from public domain software, where the author has given up that claim altogether.

Answer: A

Correct answer: CD

CD changes the current directory, and CHDIR is simply its longer spelling - the same command under two names. MOVE relocates files rather than changing where you are.

Answer: A

Correct answer: synchronize critical resources to prevent deadlock

A semaphore is an integer with atomic wait and signal operations, used to guard a shared resource so that processes take it in a disciplined order. Used correctly - every process taking the semaphores in the same order - it both enforces mutual exclusion and prevents the circular waiting that would otherwise deadlock them.

Answer: D

Correct answer: all of the above

The producer–consumer problem needs mutual exclusion on the buffer and a way to make the producer wait when it is full and the consumer wait when it is empty. Semaphores provide both directly, event counters do it without mutual exclusion by counting occurrences, and monitors package the buffer with its condition variables. All three solve it.