Editing Computer multitasking (section)

== Multithreading ==

[[Thread (computing)|Threads]] were born from the idea that the most efficient way for cooperating processes to exchange data would be to share their entire memory space. Thus, threads are effectively processes that run in the same memory context and share other resources with their [[parent process]]es, such as open files. Threads are described as ''lightweight processes'' because switching between threads does not involve changing the memory context.<ref>{{cite web
 | url = http://www.redbooks.ibm.com/redpapers/pdfs/redp4285.pdf
 | title = Linux Performance and Tuning Guidelines
 | date = April 25, 2008
 | access-date = March 1, 2015
 | author1 = Eduardo Ciliendo
 | author2 = Takechika Kunimasa
 | website = redbooks.ibm.com
 | publisher = [[IBM]]
 | page = 4
 | archive-url = https://web.archive.org/web/20150226022205/http://www.redbooks.ibm.com/redpapers/pdfs/redp4285.pdf
 | archive-date = February 26, 2015
 | url-status = dead
 }}</ref><ref>{{cite web
 | url = http://www.linfo.org/context_switch.html
 | title = Context Switch Definition
 | date = May 28, 2006
 | access-date = February 26, 2015
 | website = linfo.org
 | archive-url = https://web.archive.org/web/20100218115342/http://www.linfo.org/context_switch.html
 | archive-date = February 18, 2010
 | url-status = dead
 }}</ref><ref>{{cite web
 | url = http://www.tldp.org/FAQ/Threads-FAQ/Types.html
 | title = What are threads (user/kernel)?
 | date = September 8, 1997 | access-date = February 26, 2015
 | website = tldp.org
}}</ref>

While threads are scheduled preemptively, some operating systems provide a variant to threads, named ''[[Fiber (computer science)|fiber]]s'', that are scheduled cooperatively. On operating systems that do not provide fibers, an application may implement its own fibers using repeated calls to worker functions. Fibers are even more lightweight than threads, and somewhat easier to program with, although they tend to lose some or all of the benefits of threads on [[multiprocessing|machines with multiple processors]].<ref>[http://csmoraitis.weebly.com/uploads/1/4/1/9/14190245/multitasking_-_different_methods.pdf Multitasking different methods]

Accessed on February 19, 2019</ref>

Some systems directly support [[Multithreading (computer architecture)|multithreading in hardware]].