Computer Operating System Questions and Answers

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: D

Correct answer: all of the above

The compile-and-go scheme suffers all three drawbacks: the translator itself occupies memory that the program being run could have used; the source must be retranslated every single time the program is run; and it offers no way to combine separately translated segments, so subroutines cannot be written in another language or shared.

Answer: A

Correct answer: hardware

The operating system stands between the user and the hardware, presenting the machine in usable terms - a file rather than a set of disk sectors, a process rather than a schedule of interrupts - and doing the device-level work on the user’s behalf. Memory, peripherals and the screen are all parts of that hardware.

Answer: C

Correct answer: Thrashing is a natural consequence of virtual memory systems

Thrashing follows directly from demand paging: if the resident pages are too few for the processes running, each fault steals a frame another process needs, and the system spends its time paging rather than computing. The other statements are false - LRU pages out the least recently used pages, and seek analysis addresses device-busy rather than control-unit problems.

Answer: C

Correct answer: Both of the above

Compilation runs in phases, and both named here are among them: lexical analysis groups the source characters into tokens at the front of the process, and code generation emits the target instructions at the end, with syntax analysis, semantic analysis and optimisation in between.

Answer: D

Correct answer: All of the above

Windows is defined by all three: overlapping windows that let several programs be seen at once, pull-down menus that put each program’s commands within reach without memorising them, and icons that stand for files and programs so they can be acted on by pointing.

Answer: B

Correct answer: load-and-go assembler

A load-and-go assembler writes the machine code straight into the memory locations where it will run, producing no object file at all. That makes it fast and convenient for short programs, at the cost of retranslating the source on every run and of being unable to link separately assembled modules.

Answer: B

Correct answer: used in all major commercial operating systems

Virtual memory is universal in serious operating systems, because it lets a program exceed physical memory, isolates each process in its own address space, and allows memory to be over-committed safely. It is not simple - it needs address-translation hardware - and it uses memory more efficiently, not less.

Answer: C

Correct answer: must be "loaded" before execution

Object code is the machine code a translator produces, but it is not yet runnable: external references must be resolved by the linker and the addresses relocated to wherever the program is placed, which the loader does before control is passed to it.

Answer: A

Correct answer: a set of programs which controls computer working

An operating system is the body of programs that controls the machine - scheduling the processor, allocating memory, managing files and driving devices - and presents that machine to users and to other programs. Translating a high-level language is the compiler’s work.