Logical partition: Difference between revisions

Revision as of 08:42, 19 September 2022

Revision as of 09:04, 19 September 2022

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==PR/SM==

TheAlthough the terms ''PR/SM'' and ''LPAR'' are often used interchangeably in IBM Z, including in IBM documentation, ''PR/SM'' was not present in the [[IBM 370/168]]'s [[VM (operating system)|Virtual Machine Facility/370]]; it came in with the [[IBM 3090]], years later. Formally, LPAR designates the logical partitioning function and mode of operation, whereas PR/SM is the commercial designation of the feature.<ref name="Singh"/>{{rp|83}}

{{Short description|IBM mainframe hypervisor}}

{{primary sources|date = February 2009}}

In mainframe computing '''PR/SM''' ('''Processor Resource/System Manager''') is a type-1 [[Hypervisor]] (a [[virtual machine]] monitor) that allows multiple [[LPAR|logical partition]]s to share physical resources such as [[Central processing unit|CPU]]s, [[Channel I/O|I/O channels]] and LAN interfaces; when sharing channels, the LPARs can share I/O devices such as [[direct access storage device]]s (DASD). PR/SM is integrated with all [[IBM System z]] machines. Similar facilities exist on the [[IBM Power Systems]] family, and its predecessors.

[[IBM]] introduced PR/SM in 1988 with the [[IBM 3090]] processors.<ref>{{cite web|url=http://www.redbooks.ibm.com/redpapers/pdfs/redp5157.pdf|title=IBM Z Functional Matrix|author1=Frank Packheiser|author2=Octavian Lascu|author3=Bill White|page=18|publisher=[[IBM]]|date=2018}}</ref>

IBM developed the concept of hypervisors in their [[IBM CP-40|CP-40]] and [[CP-67]], and in 1972 provided it for the [[IBM System/370|S/370]] as Virtual Machine Facility/370.<ref>{{cite manual |url=http://www.vm.ibm.com/pubs/HCSF8A50.PDF |title=z/VM built on IBM Virtualization Technology General Information Version 4 Release 3.0 |id=GC24-5991-04 |date=April 2002 |publisher=IBM}}</ref> IBM introduced the Start Interpretive Execution ('''SIE''') instruction as part of 370-XA on the 3081, and VM/XA versions of [[VM (operating system)|VM]] to exploit it. PR/SM is a type-1 Hypervisor based on the CP component of [[VM (operating system)|VM/XA]] that runs directly on the machine level and allocates system resources across [[LPAR]]s to share physical resources. It is a standard feature on [[IBM Z]] and [[IBM LinuxONE]] machines.

IBM introduced a related, simplified, optional feature called [[Dynamic Partition Manager]] (DPM) on its IBM z13 and first generation IBM LinuxONE machines. DPM provides Web-based user interfaces for many LPAR-related configuration and monitoring tasks.

== External links ==

* {{cite web

|url = http://publib.boulder.ibm.com/infocenter/eserver/v1r2/index.jsp?topic=/eicaz/eicazzlpar.htm

|title = System z PR/SM

|url-status = dead

|archiveurl = https://archive.today/20130103052157/http://publib.boulder.ibm.com/infocenter/eserver/v1r2/index.jsp?topic=/eicaz/eicazzlpar.htm

|archivedate = 2013-01-03}}

==References==

{{Reflist}}

{{Virtualization products}}

{{DEFAULTSORT:PR SM}}

[[Category:Virtualization software]]

[[Category:IBM mainframe technology]]

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