Operating Systems: Processes, Threads, and System Architecture

A comprehensive vocabulary review of core Operating Systems topics, including process states, threading architectures, cache replacement algorithms, interrupts, and system maintenance.

ULT (User-Level Thread)

A user-created unit of execution within a process that cannot be scheduled directly by the operating system.

Operating System Evolution

The requirement that operating systems evolve over time because new hardware is designed and new services are implemented.

Operating System (OS)

The primary software system whose principal responsibility is to control the execution of processes.

Thread

A single execution path with an execution stack, processor state, and scheduling information.

Main Memory Access

An operational event during execution that does not interrupt a running process, unlike power failures, timers, or printer access.

Interrupt Handler

A routine that determines the nature of an interrupt and performs whatever actions are needed.

Replacement Algorithm

An algorithm that chooses which block to replace when a new block is to be loaded into the cache and the cache already has all slots filled with other blocks.

Suspended Process

A process that was placed in a state by an agent—either itself, a parent process, or the OS—for the purpose of preventing its execution temporarily.

Operating System Manageable Errors

A category of errors that the operating system can manage, which includes lack of paper in printer, power failure, and network connection failure.

Suspending

An operation on a process that involves moving part or all of the process from main memory to disk.

Five-State Process Diagram

A process lifecycle model that includes the states: New, Ready, Running, Blocked, and Exit.

Single-Threaded Approach

The traditional approach of a single thread of execution per process, in which the concept of a thread is not recognized.

Blocked State

The state of a process when it is located in main memory and awaiting an event.