Editing Thread (computing) (section)

===Threads vs processes===
Threads differ from traditional [[computer multitasking|multitasking]] operating-system [[process (computing)|processes]] in several ways:
* processes are typically independent, while threads exist as subsets of a process
* processes carry considerably more [[state (computer science)|state]] information than threads, whereas multiple threads within a process share process state as well as [[computer storage|memory]] and other [[resource (computer science)|resources]]
* processes have separate [[address space]]s, whereas threads share their address space
* processes interact only through system-provided [[inter-process communication]] mechanisms
* [[context switch]]ing between threads in the same process typically occurs faster than context switching between processes

Systems such as [[Windows NT]] and [[OS/2]] are said to have ''cheap'' threads and ''expensive'' processes; in other operating systems there is not so great a difference except in the cost of an [[address space|address-space]] switch, which on some architectures (notably [[x86]]) results in a [[translation lookaside buffer]] (TLB) flush.

Advantages and disadvantages of threads vs processes include:
* ''Lower resource consumption'' of threads: using threads, an application can operate using fewer resources than it would need when using multiple processes. 
* ''Simplified sharing and communication'' of threads: unlike processes, which require a [[message passing]] or shared memory mechanism to perform [[inter-process communication]] (IPC), threads can communicate through data, code and files they already share.
* ''Thread crashes a process'': due to threads sharing the same address space, an illegal operation performed by a thread can crash the entire process; therefore, one misbehaving thread can disrupt the processing of all the other threads in the application.