Computer Operating System Questions and Answers

Answer: C

Correct answer: allows each program in turn to use the memory

Swapping moves a whole process out to backing store and brings another in, so the processes take turns occupying memory rather than sharing it at the same instant. It is the coarsest form of memory management, and it is what paging refines by moving pages rather than whole processes.

Answer: C

Correct answer: Program

A program is the sequence of instructions, written in a computer language, that produces the desired result when executed. An algorithm is the method it implements, expressed independently of any language, and a decision table sets out conditions and actions as a design document.

Answer: C

Correct answer: Mode

MODE redirects printer output from a parallel port to a serial one - MODE LPT1=COM1 - and also sets the serial line’s baud rate, parity and stop bits. PRINT queues files for printing but does not redirect the port.

Answer: D

Correct answer: All of the above

The paging software does all three: it implements each program’s address environment, mapping virtual pages to frames; it manages the physical address space, deciding which frames are occupied and which page to evict; and it enforces sharing and protection, letting two processes map the same frame while denying access outside their own pages.

Answer: D

Correct answer: as several incrementals, followed by an image copy

The economical scheme is a series of incremental backups, each copying only what changed since the last, followed periodically by a full image copy that resets the chain. Incrementals are quick and small; the image copy limits how many tapes a restore has to walk through.

Answer: B

Correct answer: spooling

Spooling - simultaneous peripheral operation on line - writes output destined for a slow device to a disk queue instead, and a separate process feeds it to the device later. The program is freed at once rather than being held back to the speed of the printer, and several jobs' output can be interleaved fairly.

Answer: B

Correct answer: they are initially stored on disk

These systems are called disk operating systems because the system itself lives on disk and is loaded from there when the machine starts, rather than being held permanently in ROM as the earlier microcomputer monitors were. Managing files on disk was their central new capability.

Answer: D

Correct answer: floppy disk

Access time rises as you move away from the processor, and the floppy disk is the slowest of the four: its motor must often spin up, it turns at only a few hundred revolutions per minute, and its head steps slowly. Cache is the fastest, swapping devices are built for speed, and a hard disk is far quicker than a diskette.

Answer: B

Correct answer: Use the SETVER command

Some older programs check the DOS version and refuse to run on a later one. SETVER keeps a table of such programs and the version number each should be told, so the application sees the version it expects and runs unchanged.

Answer: D

Correct answer: one which is enclosed by a pair of P and V operations on semaphores

A critical region is the code that accesses a shared resource, and it is protected by bracketing it with the semaphore operations P (wait) and V (signal), so that only one process is inside at a time. The definition is about the protection, not about the code being buggy.