AS/400: How to perform IPL?

AS/400 Library
What are the basic steps to perform IPL in AS/400?

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Power Down System (PWRDWNSYS)

The Power Down System (PWRDWNSYS) command prepares the system for
ending and then starts the power-down sequence. All active
subsystems are notified that the system is being powered down; no
new jobs or routing steps can be started by any subsystem.

Use GO CMDPWR for other POWER commands.


enjoy life. it is not a dress rehearsal.


PWRDWNSYS will turn off your iSeries (i5 or AS/400) and to perform an IPL the command needs an additional parameter.


This will perform everything Phil says and restart your machine.



Both answers are assuming the system is actually on and he’s looking to reboot, rather than IPL’ing from an off state using the correct panel code and the power button.

Discuss This Question: 9  Replies

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  • Ibmmer
    Make sure your server wasn't put into manual mode before you IPL!
    375 pointsBadges:
  • Splat
    I'd recommend before using the PWRDWNSYS command, execute an ENDSBS SBS(*ALL) OPTION(*CNTRLD) DELAY(120). Per my CE, ending subsystems immediately tells the system not to clear the cache, so there's a possibility of data loss.
    12,895 pointsBadges:
  • mcl
    Using OPTION(*CNTRLD) probably depends on what your system is currently doing. With a typical power down you have already ended all jobs and only you are signed on - hopefully from the console. You could then end *IMMED with no problems. If you are looking to power down for a situation of a power loss (Assumption here is you are connected to a UPS, you are monitoring the UPS status and your monitoring program powers the system off after "X" minutes of power loss.) then using a controlled end is a good idea. You use the restart *YES only if you are going to restart immediately. You should be aware that the OS has options for scheduled power off and on. If you use the scheduled power off, plan your operations around shutting down jobs beforehand to reduce the chance of any issues.
    2,740 pointsBadges:
  • WM
    Hey guys, isn't there like an Operators manual that actually guides you step by step on how to IPL the system? My suggestion is to get a hold of this manual depending on your operating system version and release.
    460 pointsBadges:
  • Gmil494
    Depends on what kind of IPL you want, need or desire. If manual (attended) IPL The codes and display could vary depending on the model/OS: the front panel LCD for a manual could show 01 BM (I believe this is the manual-attended IPL mode). If an automatic IPL is selected (there are buttons on front to page/scroll thru the options, along with entere button and power button) it likely will show 01 BN in the display (as long as power connected and AS/400 running or shutdown) is likely an automatic IPL. If in automatic IPL all you should have to do is push the power button in (exception would be if system value in some options were changed to auto IPL after power restored, or shutdown and immediate IPL are specified in system options/config.) and the system will IPL without operator/QSECOFR intervention. If your system does not show 01 BN (or some other possible changed code or alternate code) for automatic IPL, from OS/400 V4R2 and later you have to enter a system password (if in auto IPL mode this likely has already been done so you don't have to enter it). You can IPL without a system password for about 70 days, after which if you don't have a system password, the machine will no longer IPL. To shutdown the system: PWRDWNSYS *CNTLD (may take some time to shutdown depending on workload/subsystems etc - OR - PWRDWNSYS *IMMED (immediate shutdown) is not instantaneous but takes about 10-15 minutes. ENDSBS (*ALL) may be a better choice before entering the desired PWRDWNSYS. But I read somewhere that if certain subsystems are not allowed to complete processing an abnormal shutdown could ensue, and that would require a longer IPL while the system recovers from the abnormal shutdown. I contemplated setting the system config/value to auto IPL on power restoration, but after thinking, if you have a storm, water leak, fire, etc, where automatically bringing the machine up after short or prolonged loss of power may not be wise (water dripping on your machine will not extend its life... and will surely fry it once water and electricity mix). A manual IPL requires (mode has to be chosen on front panel for the various modes) you (OS/400 V4R2 and later) to enter a system password, new unique system identifier, proceed thru some other requirements and options and eventually select to IPL. You'll be prompted each step of the way. You can find good info online at IBM' AS/400//iSeries web online resource "boulder co. site" Also the book: The As/400 Owner's Manual for V4 by Mike Dawson (MC Press) is a good reference (not completely exhaustive and dealing with all detail, some chapters refer to IBM manuals.
    365 pointsBadges:
  • Gmil494
    FYI: I just tried the ENDSBS command, from command line, and prompted (F4), I either way I received a message "command not available in/from this environment" I'm sure the logic to end subsystems before issuing the PWRDWNSYS command is correct and good advice. But if issuing the ENDSBS command does not shutdown the (especially considering the message I received via command line and prompted entry) subsystems in correct order, one could still use one or two commands to list subsystems, but if you don't know which should (or correct sequence of subsystems to shutdown in order) be shutdown, you could / would still end up with an abnormal shutdown, or could do more damage than issuing the PWRDWNSYS command, where if cache/data loss problems arise as mentioned earlier in this dialogue.
    365 pointsBadges:
  • graybeard52
    ENDSBS *ALL needs to be run from the QCTL subsystem - usually just the system console.
    3,115 pointsBadges:
  • syspence33
    use tfrjob jobq(QCTL)
    10 pointsBadges:
  • MrObvious

    GO POWER, (opt) 4, F16 (to confirm)

    is power down immediately and restart.

    power down on my box takes 3 minutes, IPL coming back up takes 25 minutes, (takes another 10 minutes to load our software.)

    I can have my system downed and back up in 45 minutes.

    on the other hand an unattended IPL via wrkjobscde on the weekend takes 1.5 hours.

    the difference is endsbs (immed) vs (controlled)

    controlled shutdown on my box w/IPL takes twice as long as immed.

    i suggest you check your wrkjobscde before you IPL, the jobs scheduled to run.. will run.. if scheduled and not put on hold.  the IPL checks that list during IPL.

    250 pointsBadges:

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