OS GLOSSARY

Question 1

Address Space

Answer 1

The set of memory addresses that a process can access.

Question 2

Base and Bound

Answer 2

A memory protection mechanism that limits a process’s access to a specific range of memory addresses.

Question 3

Context Switch

Answer 3

The process of saving the state of a running process or thread and loading the state of another process or thread to resume execution.

Question 4

CPU Scheduling:

Answer 4

The OS mechanism for selecting which process or thread will execute next on the CPU.

Question 5

Deadlock:

Answer 5

A situation where two or more processes are blocked indefinitely, each waiting for a resource held by another.

Question 6

Direct Memory Access (DMA):

Answer 6

Allows certain hardware subsystems to access main memory independently of the CPU.

Question 7

Dual-Mode Operation:

Answer 7

A hardware feature that allows the OS to operate in two modes: user mode and kernel mode.

Question 8

File System:

Answer 8

Part of the OS that provides a logical view of persistent storage, organizing files and directories.

Question 9

Fork():

Answer 9

A system call that creates a new process (a child process) that is a copy of the calling process (the parent process).

Question 10

Interrupt:

Answer 10

A hardware or software signal that disrupts the normal execution of the CPU and transfers control to a specific interrupt handler.

Question 11

Kernel Mode:

Answer 11

The privileged mode of the OS, allowing access to all hardware resources.

Question 12

Multiprogramming:

Answer 12

A technique that allows multiple processes to share a single CPU, giving the illusion of parallelism.

Question 13

Process:

Answer 13

An instance of a running program, with its own address space, resources, and execution state.

Question 14

Process Control Block (PCB):

Answer 14

A kernel data structure that stores information about a process.

Question 15

Race Condition:

Answer 15

A situation where the outcome of a program depends on the unpredictable timing of events or the order of execution of concurrent threads.

Question 16

Scheduler:

Answer 16

The OS component responsible for selecting which process or thread will execute next.

Question 17

Signal:

Answer 17

A software mechanism in UNIX-like OSes for asynchronous notification of events to a process.

Question 18

System Call (Syscall):

Answer 18

A programmatic way for a process to request services from the OS kernel.

Question 19

Thread:

Answer 19

A lightweight unit of execution that shares an address space and resources with other threads within the same process.

Question 20

User Mode:

Answer 20

The non-privileged mode in which user applications typically execute.

Question 21

Virtual Memory:

Answer 21

A memory management technique that provides the illusion of a larger physical memory space than is actually available.

Question 22

Virtual Machine (VM):

Answer 22

Software that creates an abstraction of a physical computer, allowing multiple operating systems to run concurrently on the same physical machine.