OS GLOSSARY Flashcards
Address Space
The set of memory addresses that a process can access.
Base and Bound
A memory protection mechanism that limits a process’s access to a specific range of memory addresses.
Context Switch
The process of saving the state of a running process or thread and loading the state of another process or thread to resume execution.
CPU Scheduling:
The OS mechanism for selecting which process or thread will execute next on the CPU.
Deadlock:
A situation where two or more processes are blocked indefinitely, each waiting for a resource held by another.
Direct Memory Access (DMA):
Allows certain hardware subsystems to access main memory independently of the CPU.
Dual-Mode Operation:
A hardware feature that allows the OS to operate in two modes: user mode and kernel mode.
File System:
Part of the OS that provides a logical view of persistent storage, organizing files and directories.
Fork():
A system call that creates a new process (a child process) that is a copy of the calling process (the parent process).
Interrupt:
A hardware or software signal that disrupts the normal execution of the CPU and transfers control to a specific interrupt handler.
Kernel Mode:
The privileged mode of the OS, allowing access to all hardware resources.
Multiprogramming:
A technique that allows multiple processes to share a single CPU, giving the illusion of parallelism.
Process:
An instance of a running program, with its own address space, resources, and execution state.
Process Control Block (PCB):
A kernel data structure that stores information about a process.
Race Condition:
A situation where the outcome of a program depends on the unpredictable timing of events or the order of execution of concurrent threads.
Scheduler:
The OS component responsible for selecting which process or thread will execute next.
Signal:
A software mechanism in UNIX-like OSes for asynchronous notification of events to a process.
System Call (Syscall):
A programmatic way for a process to request services from the OS kernel.
Thread:
A lightweight unit of execution that shares an address space and resources with other threads within the same process.
User Mode:
The non-privileged mode in which user applications typically execute.
Virtual Memory:
A memory management technique that provides the illusion of a larger physical memory space than is actually available.
Virtual Machine (VM):
Software that creates an abstraction of a physical computer, allowing multiple operating systems to run concurrently on the same physical machine.
