The installation of microcode PTFs (MFxxxxx) requires two IPLs when you want to apply them temporarily. As IBM recommends to always run on the "B" side, to apply these PTFs you must perform an IPL from the "A" side and then back from the "B" to have the PTFs in effect.
This can be done unattended, so you don't have to watch your machine doing IPLs, a lengthy process for some, and it can be done during the nighttime to avoid downtime during the day.
You need to have V2R1 installed. After you have loaded the PTFs, apply them with the following parameters: APY(*TEMP) DELAYED (*YES).
Assuming you are running on the "B" side, change the IPL source from the control panel as follows:
1. Turn the keylock switch to MANUAL. 2. Press the Select switch until 02 is displayed. 3. Press the Enter button. 4. Press the Select switch until "A" appears. 5. Press the Enter button. 6. Turn the keylock switch to NORMAL position and leave the machine running.
On a command line, enter GO POWER and select Option 2 (change power on and off schedule).
For example, I want the PTFs to be applied during the weekend. For the next Saturday, I schedule a power off at 23:00 and power on at 23:40.
For the Sunday, power off at 00:30 and power on at 01:10.
The system will first IPL from "A" and temporarily apply the PTFs. The second IPL will automatically be performed from "B".
Your PTFs are now in effect.
Editor's Note: Disk IPLs can be made from two different sources. Source A contains the permanent version of the operating system, including all PTFs that have been applied permanently. Source B, on the other hand, contains PTFs applied temporarily. Normally you should IPL your system from source B.
You may have to change the power off and power on times suggested by the author to suit your own installation. For example, his system could be powered down at 23:00 and powered back up at 23:40. Your system may take longer than 40 minutes to complete this cycle. If in doubt, give it more time than necessary.