Computer Operating System Questions and Answers

Q: The deleted file in Microsoft Disk Operating System (MS-DOS) can be recovered immediately, if you use the command mention below, the command is

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.

Q: Which of the following is not an Operating System ?

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.

Q: What value should be used in chmod instruction in LINUX to provide read/write/execute permission of files to all, i.e., owner, user, others.

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.

Q: Where do you find the number of cores of the CPU in Windows 11 ?

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.

Q: What is defragment in Windows 11 ?

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.

Q: What is the name of the operating system that reads and reacts in terms of actual time

Correct answer: Real time systemA real-time system must respond within a deadline set by the process it controls, because a correct answer that arrives late is useless - the world has moved on. Batch and time-sharing systems aim at throughput and fair response instead, with no guaranteed deadline.

Q: What is the name given to the software which can be legally compiled and often used for free?

Correct answer: Public domain programA public domain program carries no copyright restriction, so anyone may compile, use, change and redistribute it freely. Shareware is copyrighted and may be tried before purchase but must then be paid for, and firmware describes where a program is stored rather than its licence.

Q: Process is

Correct answer: a program in executionA 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.

Q: Which among the following Windows do not have Start button

Correct answer: Windows 8Windows 8 dropped the Start button from the desktop taskbar, replacing the Start menu with the full-screen Start screen - a change so unpopular that Windows 8.1 restored the button and Windows 10 restored the menu. Vista and 7 both have it.

Q: Which of the following capabilities is required for a system program to execute more than one program at a time?

Correct answer: multitaskingRunning more than one program at a time requires multitasking: the system must hold several programs, keep the state of each, and switch the processor between them quickly enough that all appear to advance together. Virtual memory helps by letting them all be resident, but it is the switching that makes concurrency.

11.

The deleted file in Microsoft Disk Operating System (MS-DOS) can be recovered immediately, if you use the command mention below, the command is

A.DO NOT DELETE
B.NO DELETE
C.UNDELETE
D.ONDELETE

Exam Year(s)

Tripura Public Service Commission - 2019,

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.

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12.

Which of the following is not an Operating System ?

A.Windows XP
B.COBOL
C.Unix
D.Windows 10

Exam Year(s)

Tripura Public Service Commission - 2021,

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.

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13.

What value should be used in chmod instruction in LINUX to provide read/write/execute permission of files to all, i.e., owner, user, others.

A.111
B.333
C.555
D.777

Exam Year(s)

Tripura Public Service Commission - 2026,

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.

Discuss in Forum

14.

Where do you find the number of cores of the CPU in Windows 11 ?

A.Memory
B.CPU
C.Ethernet
D.Disk

Exam Year(s)

Tripura Public Service Commission - 2026,

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.

Discuss in Forum

15.

What is defragment in Windows 11 ?

A.Optimize Disk
B.Optimize RAM
C.Optimize CPU
D.None of these

Exam Year(s)

Tripura Public Service Commission - 2026,

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.

Discuss in Forum

16.

What is the name of the operating system that reads and reacts in terms of actual time

A.Batch system
B.Quick response system
C.Real time system
D.Time sharing system

Answer: C

Correct answer: Real time system

A real-time system must respond within a deadline set by the process it controls, because a correct answer that arrives late is useless - the world has moved on. Batch and time-sharing systems aim at throughput and fair response instead, with no guaranteed deadline.

Discuss in Forum

17.

What is the name given to the software which can be legally compiled and often used for free?

A.Shareware program
B.Public domain program
C.Firmware program
D.Mindware

Answer: B

Correct answer: Public domain program

A public domain program carries no copyright restriction, so anyone may compile, use, change and redistribute it freely. Shareware is copyrighted and may be tried before purchase but must then be paid for, and firmware describes where a program is stored rather than its licence.

Discuss in Forum

18.

Process is

A.program in High level language kept on disk
B.contents of main memory
C.a program in execution
D.a job in secondary memory

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.

Discuss in Forum

19.

Which among the following Windows do not have Start button

A.Windows Vista
B.Windows 7
C.Windows 8
D.None of above

Answer: C

Correct answer: Windows 8

Windows 8 dropped the Start button from the desktop taskbar, replacing the Start menu with the full-screen Start screen - a change so unpopular that Windows 8.1 restored the button and Windows 10 restored the menu. Vista and 7 both have it.

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20.

Which of the following capabilities is required for a system program to execute more than one program at a time?

A.word processing
B.compiling
C.virtual memory
D.multitasking

Answer: D

Correct answer: multitasking

Running more than one program at a time requires multitasking: the system must hold several programs, keep the state of each, and switch the processor between them quickly enough that all appear to advance together. Virtual memory helps by letting them all be resident, but it is the switching that makes concurrency.

Discuss in Forum

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