Computer Operating System Questions and Answers

Answer: D

Correct answer: should be chosen to match the data characteristics

Record length is a design decision, not a rule: fixed-length records are simpler and allow a record’s position to be computed directly, while variable-length records waste no space when the data itself varies greatly in size. The right choice follows from what the data looks like.

Answer: B

Correct answer: DBLSPACE

DBLSPACE is DOS 6’s disk compression: it can compress an existing drive in place or create a new compressed volume, storing the data in a hidden compressed volume file that a driver presents as an ordinary drive letter. DEFRAG only rearranges files and SCANDISK only checks them.

Answer: A

Correct answer: JCL

Special forms, and the printer they are to be mounted on, are described to the operating system in the job’s job control language statements - the DD statement naming the form number, so the operator is prompted to mount it before the job prints.

Answer: D

Correct answer: index mode

In index addressing the effective address is the constant in the instruction plus the contents of the index register, so the constant names the start of an array and the register selects the element. Stepping the register walks through the array without changing the instruction.

Answer: C

Correct answer: is a mnemonic form of machine language

Assembly language corresponds one instruction to one machine instruction, but writes the operation codes as mnemonics such as MOV and the addresses as symbolic labels, which the assembler translates back to binary. That is why it is described as the mnemonic form of machine language.

Answer: A

Correct answer: creates a load module

A linker takes the object modules produced by the translator, resolves the external references between them, and combines them into one load module ready for the loader to place in memory. It is needed whenever a program is built from more than one separately compiled part.

Answer: B

Correct answer: real-time software

Real-time software measures, monitors, analyses and controls events as they happen, and must respond within a guaranteed time - an answer that arrives late is as useless as a wrong one. Process control, avionics and instrumentation systems are of this kind.

Answer: B

Correct answer: Specify, to the operating system, the beginning and end of a job in a batch

JCL statements bracket and describe a batch job for the operating system: the JOB statement marks its start and gives the accounting information, EXEC statements name the programs to run, and DD statements describe the data sets they use. JCL declares what is wanted; it does not itself move data or allocate the processor.

Answer: B

Correct answer: UNDELETE *.DOC

UNDELETE takes a file specification, so UNDELETE *.DOC offers back each deleted file matching that pattern. It works because deletion only marks the directory entry and frees the clusters; the data survives until something else is written over it.

Answer: B

Correct answer: macro

A macro is a single statement that the assembler or compiler replaces, before translation, with the sequence of instructions its definition holds - substituting the actual arguments for the formal parameters. Unlike a procedure call, the code is expanded in line, so nothing is branched to at run time.