Swapping - Revision history

Jnc: +cat

2018-12-15T19:38:19Z

+cat

Jnc: Proper cat

2018-10-21T13:39:06Z

Proper cat

Jnc: Mention base+bounds

2018-04-15T19:13:17Z

Mention base+bounds

Jnc: A good start

2018-04-15T19:08:09Z

A good start

New page

'''Swapping''' is the term for moving the contents of a [[process]]' [[address space]], as a unitary entity, back and forth between [[main memory]] and [[secondary storage]], when there are more processes active than can be accomodated simultaneously in main memory.

For a number of reasons, it has largely been superseded by [[virtual memory|paging]], the most important of which being that the smallish fixed size of pages, and the ability to scatter the pages of a process, with them not needing to be contiguous, makes the allocation of physical memory much simpler in paging.

Swapping of a sort may still be used in some [[operating system]], in that a process which has gone inactive may have all its pages removed from main memory to leave more room for ones that are active. Also, if the system is so overloaded that it is [[thrashing]], swapping entire proccesses out may be the appropriate response.

{{stub}}

← Older revision		Revision as of 19:38, 15 December 2018
Line 8:		Line 8:

	{{semi-stub}}		{{semi-stub}}
		+
		+	[[Category: OS Basics]]

← Older revision		Revision as of 13:39, 21 October 2018
Line 7:		Line 7:
	Swapping of a sort may still be used in some [[operating system]]s, in that a process which has gone inactive may have all its pages removed from main memory to leave more room for ones that are active. Also, if the system is so overloaded that it is [[thrashing]], swapping entire proccesses out may be the appropriate response.		Swapping of a sort may still be used in some [[operating system]]s, in that a process which has gone inactive may have all its pages removed from main memory to leave more room for ones that are active. Also, if the system is so overloaded that it is [[thrashing]], swapping entire proccesses out may be the appropriate response.

−	{{stub}}	+	{{semi-stub}}

@@ Line 1: / Line 1: @@
 '''Swapping''' is the term for moving the contents of a [[process]]' [[address space]], as a unitary entity, back and forth between [[main memory]] and [[secondary storage]], when there are more processes active than can be accomodated simultaneously in main memory.
-For a number of reasons, it has largely been superseded by [[virtual memory|paging]], the most important of which being that the smallish fixed size of pages, and the ability to scatter the pages of a process, with them not needing to be contiguous, makes the allocation of physical memory much simpler in paging.
+For a number of reasons, it has largely been superseded by [[virtual memory|paging]], the most important of which being that the smallish fixed size of pages, and the ability to scatter the pages of a process, without the need to have them be contiguous, makes the allocation of physical memory much simpler in paging.
-Swapping of a sort may still be used in some [[operating system]], in that a process which has gone inactive may have all its pages removed from main memory to leave more room for ones that are active. Also, if the system is so overloaded that it is [[thrashing]], swapping entire proccesses out may be the appropriate response.
+It was the usual technique in systems whose hardware did not support paging, i.e. those which did [[memory management]] using [[base and bounds]] [[register]]s.
 {{stub}}