Dual-booting NeXTStep and HP-UX on HP 712

Breaking this up from the What have you done with your NeXT computer today discussion (https://www.nextcomputers.org/forums/index.php?topic=5605.msg31960#msg31960):

Quote from: paolo.bertolo on April 28, 2024, 09:45:22 PM

Quote2.  Recently acquired an HP 712/60 pizza box, which after I recap the power supply, will setup either a dual boot to HP/UX and NeXTSTEP or just dedicated NeXTSTEP...haven't decided on that one.

I'm afraid it's not possible, it's clearly indicated in the installation guide of NEXTSTEP 3.3 for PARISC. Best you can have is the two OSes installed on two different SD cards and swap them.

I've been thinking about this and just made a little experiment. The FAQ (https://www.nextop.de/NeXTAnswers/1684.html#hp-uxandnextstep) actually says: "HP-UX and NEXTSTEP use incompatible partitioning schemes and cannot be installed on the same disk. The only way to set up a dual-boot machine is by using separate hard disks for HP-UX and NEXTSTEP".

I've seen other places where this has been put simply as "not possible at all". Having only one internal HD bay, dual-booting a 712 would've required using an external disk (which is why this might've been put as not feasible), but as ZuluSCSI etc. can emulate several SCSI devices it seems to be quite possible to dual-boot (from two separate disk image files).

I just set my HP 712/60 up like this:

1) Internal ZuluSCSI with:
- NeXTStep image as SCSI ID 6 (with sectorsPerTrack = 139 and headsPerCylinder = 4 set in the zuluscsi.ini file)
- HP-UX 9 image as SCSI ID 5

2) When booting, press ESC to escape the boot sequence and go into the HP's boot monitor and use the following commands:
- "search scsi" -> show available disks, should show the two drives
- "path pri scsi.6" -> set primary boot device to SCSI ID 6 (NS in my case)
- "path alt scsi.5" -> set alternative boot device to SCSI ID 5 (HP-UX)

3) Powering up the system will now boot NS by default. Powering up, and pressing ESC & typing "boot alt" will boot HP-UX.

4) HP-UX will ignore the NS disk and work as usual, but NS detects the HP-UX disk as unreadable and asks to ignore/initialize it on every boot. To set NS to permanently ignore the HP-UX drive, add something like "/dev/sd1a /hpux ignore ro 0 0" into the /etc/fstab file. (Booting NS will show the naming scheme for the drives as "The following scsi disks have been found...")

This seems to do the trick and I can boot both systems like this! Anyone care to test and verify? I am sure using proper commands both NS and HP-UX can mess up the other drive, but so far this seems to work.

Only issue I can see is that HP-UX 9 has trouble with Y2K dates and might mess up the clock, but if networked, a NS user can always run something like "ntp -s -f (local ntp server's IP here)" to set the time.

If there is a file system that both NS and HP-UX can read-and-write, then perhaps a third SCSI ID could be used as a common disks to exchange files between the two OS'?

Hey @MindWalker.

Taking your outlined steps, I did the exact setup as noted and everything worked as expected.

You mentioned something about time being possibly messed up when going between HP/UX and NS 3.3.  A way to solve this to ensure that your timezone is set correctly in NS and put the following into the rc.local file.  This will set the time prior to getting into Workspace.  Not having to type manual commands on a regular basis and letting the silicon do the work for the carbon, works a treat.  😁

(echo 'Setting current date/time using time.apple.com.') >/dev/console
fbshow -B -I "Setting current date/time using time.apple.com." -z 92
ntp -s -f time.apple.com
Y2K dates for HP/UX 9 was fixed in a rare, hard to find release of 9.10.  I found something that looks promising for possible download and further testing of that.  https://www.betaarchive.com/database//view_release.php?uuid=081bbdfd-d276-477c-9924-0ccda298bb71

It's nice now not to have to swap out SD cards to go between NS 3.3 and HP/UX.  =)