Editing Protected mode (section)

=== Multitasking ===
{{details|Computer multitasking}}

Through the use of the rings, privileged [[call gate]]s, and the [[Task State Segment]] (TSS), introduced with the 286, [[preemptive multitasking]] was made possible on the x86 architecture. The TSS allows general-purpose registers, segment selector fields, and stacks to all be modified without affecting those of another task. The TSS also allows a task's privilege level, and I/O port permissions to be independent of another task's.

In many operating systems, the full features of the TSS are not used.<ref name="TSS Usage">{{ cite web | url = http://neworder.box.sk/newsread.php?newsid=10562 | work = NewOrer | title = news: Multitasking for x86 explained #1 | access-date = 2007-07-29 | author = zwanderer | date = May 2, 2004 | format = Article | publisher = NewOrder | quote = The reason why software task switching is so popular is that it can be faster than hardware task switching. Intel never actually developed the hardware task switching, they implemented it, saw that it worked, and just left it there. Advances in multitasking using software have made this form of task switching faster (some say up to 3 times faster) than the hardware method. Another reason is that the Intel way of switching tasks isn't portable at all | archive-url = https://web.archive.org/web/20070212161434/http://neworder.box.sk/newsread.php?newsid=10562 | archive-date = 2007-02-12 }}</ref> This is commonly due to portability concerns or due to the performance issues created with hardware task switches.<ref name="TSS Usage" /> As a result, many operating systems use both hardware and software to create a multitasking system.<ref name="Uses both">{{ cite web | url = http://neworder.box.sk/newsread.php?newsid=10562 | work = NewOrer | title = news: Multitasking for x86 explained #1 | access-date = 2007-07-29 | author = zwanderer | date = May 2, 2004 | format = Article | publisher = NewOrder | quote = ...&nbsp;both rely on the Intel processors ability to switch tasks, they rely on it in different ways. | archive-url = https://web.archive.org/web/20070212161434/http://neworder.box.sk/newsread.php?newsid=10562 | archive-date = 2007-02-12 }}</ref>