Information Systems:IBM i restricted state
Overview
Restricted state on IBM i refers to a particular OS environment/state of limited functionality (similar to Safe Mode in Windows). From IBM's website:
Many recovery procedures require that your system have no other activity on it. When no subsystems except the controlling subsystem are active on your system, it is in a restricted state.
For the overnight process, there is a similarly limited but custom environment/state that the system enters. Sheila used the term application restriction state to describe this state, and system restricted state to refer to IBM's definition.
The Disaster Recovery article also goes into detail about restricted states. That information is worth reading but may be merged here in the near future.
System restricted state
As mentioned, this term refers to a state where only the controlling subsystem is active. For the most part this subsystem is QCTL, but in rarer occasions, can also be QBASE (depending on what the system value QCTLSBSD is set to). The best way to enter this state is through an IPL, as "Boot system into restricted state" is one of the parameters when performing an IPL. Read more about restricted state here.
Will write more here, but system restricted state is more understandable as it is clearly defined. Application restricted state requires more of an explanation; see next section.-norwizzle (talk) 13:25, 8 December 2016 (PST)
Application restricted state
Note: This section should be validated for accuracy by Sheila. It was written based on Norwin's interpretation of her definition.
Definition
Application Restricted State is a term coined by Sheila to describe a particular OS state/environment required to perform some ASW-related tasks in the overnight process. As part of EODEND2 - the process that prepares the system for the overnight process - all subsystems with the exception of QCTL and UP1480BS are shutdown. Therefore, in a simplified way, application restricted state can be seen as system restricted state + UP1480BS (recall that having QCTL as the only active subsystem is what defines system restricted state). However, there are additional points defining application restricted state:
- When you enter system restricted state through the IPL option, the QCTL subsystem is started in a restricted mode as well. As a consequence, the job queue QCTL cannot accept jobs. (Or types of jobs? Admittedly, this is still a gray area that I have to do more research on. -norwizzle (talk) 13:25, 8 December 2016 (PST)) However, when entering application restricted state through EODEND2, the system is running normally so the QCTL subsystem is in a normal state. In this state, batch jobs like the BRMS backup can be submitted to the QCTL job queue.
- Though UP1480BS is active in application restricted state, EODEND2 actually shuts it down first for the temporary backup by issuing an ENDSBS, then starts it back up through the CHGASWCOM (Change ASW Company) command. Whether or not this is a simple stop-and-start to accommodate the temporary backup or whether this starts the subsystem in a special way (perhaps the temporary backup leaves the ASW company as PL?) is uncertain.
Notes
- Summary:
- For system administration of the OS (PTFs, IPL etc.), restricted state refers to the official restricted state as defined by IBM.
- For administration of uniPHARM end-of-day processes, application restricted state becomes relevant. It has little relevance outside the context of end-of-day processing.
- The options in the GO DISASTER menu to start all processes recovers the system from an application restricted state. The option to end all processes puts the system in a system restricted state, but does not the set QCTL to restricted mode. Perform an IPL with the 'Boot into restricted state' option to put the system in restricted state in its most technically accurate definition.