Computer Operating System Questions and Answers

Answer: C

The command is UNDELETE.

MS-DOS 5.0 and later include UNDELETE, which recovers a deleted file as long as its disk space has not yet been reused. That is why it should be used immediately after the deletion.

DO NOT DELETE, NO DELETE and ONDELETE are not MS-DOS commands.

UNDELETE works because deleting a file in DOS only marks its directory entry and frees its clusters; the data stays on the disk until new files overwrite it, which is why the recovery should be attempted at once.

Answer: B

The one that is not an operating system is COBOL.

COBOL (Common Business-Oriented Language) is a programming language, developed around 1959 for business data processing and still used in banking and government systems.

Windows XP, Windows 10 and Unix are all operating systems, the software that manages a computer's hardware and runs other programs.

Answer: D

The value is 777.

In octal chmod notation each digit gives the permissions of one class (owner, group, others), and each digit is the sum of read = 4, write = 2 and execute = 1. Full read, write and execute is 4 + 2 + 1 = 7, so 7 for every class is 777. (The paper's 'owner, user, others' means owner, group, others.)

111 gives execute only, 333 gives write and execute, and 555 gives read and execute to everyone; none of them grants all three permissions.

Answer: B

You find it under CPU.

In Windows 11, open Task Manager (Ctrl + Shift + Esc) and go to the Performance tab. Selecting CPU shows the processor's name, speed and utilisation, together with the number of Cores and Logical processors.

The Memory, Ethernet and Disk panes on the same tab show RAM, network and storage figures, not the processor's cores.

Answer: A

Defragmenting in Windows 11 means to Optimize Disk.

The built-in tool is called Defragment and Optimize Drives. On a hard disk it gathers the scattered pieces of files into contiguous blocks so they can be read faster; on a solid-state drive it sends TRIM commands instead. Either way, it works on the disk drives.

RAM and the CPU are not defragmented by this tool, so those options and 'None of these' are wrong.

Answer: A

Correct answer: Operation code

A machine instruction has two parts: the operation code, which tells the processor what to do - add, load, branch - and the address field, which says what to do it to. The control unit decodes the opcode and issues the signals that carry it out.

Answer: C

Correct answer: there is no need for an address i.e. the data is used as an address

Associative or content-addressable memory is searched by content rather than by location: a pattern is presented and every cell compares itself with it simultaneously, returning the matching entry in one cycle. It is what makes a translation lookaside buffer and a cache tag store fast enough to be useful.

Answer: B

Correct answer: 1

A critical section is code that touches a shared resource, and a race condition arises exactly when two processes are inside one at the same time. Mutual exclusion therefore admits at most one process at a time - which is why the guarding semaphore is initialised to 1.

Answer: B

Correct answer: linking loader

A linking loader takes the separately compiled object modules, resolves the external references between them, relocates their addresses to the area of memory they are to occupy, and loads the result ready to run - combining linking and loading in one pass.

Answer: C

Correct answer: a program in execution

A program is a passive file of instructions on disk; a process is that program actually running, with a program counter, registers, a stack, its own address space and an entry in the process table. One program may have several processes running from it at once.