Computer Operating System Questions and Answers

Answer: C

Correct answer: decreased operating-system overhead

Multiprogramming increases operating-system overhead, because the system must now schedule processes, switch contexts, protect one program’s memory from another and manage contention for devices - so that is not an advantage. The gains are the other three: higher throughput, shorter response time, and the ability to give jobs priorities.

Answer: A

Correct answer: A logical error in a program

A bug is a defect that makes a program behave wrongly - typically a logical error, where the code compiles and runs but computes the wrong result, so only testing reveals it. A syntax error is caught by the compiler before the program can run at all.

Answer: D

Correct answer: All of the above

COPY does all three: it copies files from one disk to another, it copies within the same disk or directory when a new name is given, and with the + operator it concatenates two or more files into one. All are ordinary uses of the command.

Answer: D

Correct answer: track the beginning and ending of programs

Boundary registers hold the lower and upper limits of the area a program may use. Every address the program generates is compared against them, and a reference outside the pair is trapped - which is how one program is prevented from reaching into another’s memory.

Answer: D

Correct answer: All of the above

MODE is a general device-configuration command: it reports the devices installed, sets printer characteristics such as columns and lines per inch, redirects a parallel port to a serial one, sets the serial line parameters, and changes the display mode. All three descriptions are things it does.

Answer: B

Correct answer: COPY FILE1+FILE2 FILE3

COPY concatenates when its sources are joined with +: COPY FILE1+FILE2 FILE3 reads the two in turn and writes them one after the other into FILE3. The sources come first and the destination last, as in any COPY.

Answer: A

Correct answer: COM

A .COM file is a command file: a program image loaded into a single 64 KB segment and run from its first byte, with no relocation header. .EXE holds larger programs, .BAT a list of commands, and .SYS a driver.

Answer: B

Correct answer: requires detailed system performance information

Capacity planning forecasts whether the installation will meet its service targets as the workload grows, and that forecast can only be built on measured data - processor and device utilisation, queue lengths, response times, paging rates. It depends heavily on the monitoring tools available, and small installations need it too.

Answer: A

Correct answer: hold and wait

Coffman’s four conditions are mutual exclusion, no preemption, circular wait and hold and wait - a process holding one resource while waiting for another. All four must hold simultaneously for deadlock, so breaking any one of them prevents it.

Answer: B

Correct answer: These charts cannot represent CASE constructs

Nassi–Shneiderman charts represent all the structured constructs, including selection with many branches - the CASE structure is drawn as a fan of columns beneath a divided box - so that statement is untrue. The others are correct: they are a graphical design tool and they show sequence, selection and iteration.