I did this exercise a couple years ago,? and I used John Yagers zzsa disk editor?

utility to change the volser? on a copy of? VmR6.

You can get zzssa from the CBT tape site

Mike

On Tue, Jan 16, 2024, 15:05 Bob Polmanter <wably@...> wrote:

Hi Daniel,

Generally, its pretty easy to do and the effort is about the same as it is to get MVS to run under VM.? Basically, you need to:
1. have a second VM system with which to ipl as a guest of the first VM system.
2. make a directory entry in first level VM that describes the second level machine layout (dasd, console, printers, memory size, etc).
3. add the second level VM's dasd entries to Hercules (in conjunction with first-level's dasd)
4. ipl first level.? make sure all of the second level dasds are online and "available"
5. logon to the second level userid,? Assign a console for second level from one of your first level terminals making sure the virtual address is what the second level VM needs.?? Make sure your second level dasd are available to the second level userid (they should show up in a CP Q V DASD command); attach them from first level if necessary.?
6. ipl second level from the second level userid with the CP IPL command.

The hardest part of this is having a second VM system that you can use that does not have the same volume names as your first level system.? So you wouldnt want to try to use two copies of VM/CE, but you could use a VM/CE and a VM Sixpack for example if there are no duplicated volume serials.? I changed all of my Sixpack volume serials years ago to be unique from the distribution mainstream so I can't recall now if Sixpack names are duplicated in VM/CE.

You actually can use a copy of your existing dasd, but I wouldn't recommend doing it.? You need to know exactly what you are doing, what you assign to what, and what virtual addresses belong to what real device because CP won't like the duplicates and force them offline and if? you get something wrong you could clobber one or both systems.

Regards,
Bob