Setting up a combined 68k/PA-RISC HP-UX 9 cluster

Jonathan Pallant got lucky and managed to score a massive haul of ’90s UNIX workstations, one of which was an HP 9000 Model 340, a HP-UX workstation built around a Motorola 68030 processor at 16.7 MHz. It doesn’t come with a hard drive or even a floppy controller, though, so he decided to borrow a PA-RISC-based HP 9000 Model 705 to set up an HP-UX 9 cluster. But wait, how does that work, when we’re dealing with two entirely different architectures?

What’s more fun though, is putting it into a cluster with the Model 705 and network booting it.

Yes, that a 68030 machine network booting from a PA-RISC machine … and sharing the same root filesystem. But aren’t PA-RISC binaries and 68K binaries quite different? Oh yes, they really are. So, how does that work?
↫ Jonathan Pallant

HP-UX is far more interesting and fascinating than a lot of people give it credit for, and while my interest lies with HP-UX 11i, I find what Pallant is doing here with HP-UX 9 just as fascinating. You first need to install HP-UX 9 for PA-RISC on the 700 series machine, convert it to a cluster server, and then install HP-UX 9 for 68k on top of that PA-RISC installation. After this is done, you effectively end up with a single root file system that contains both PA-RISC and 68k binaries, and you can network boot the 68k-based Model 340 right from it – using the same root filesystem on both machines.

Absolutely wild.

No, these are not universal binaries or some other trick you might know of from more modern system. In fact, installing the 68k version of HP-UX 9 “into” the PA-RISC HP-UX 9 cluster server, you end up with something called a Context Dependent Filesystem. To get a better idea of what this means and how this works, you should really head on over to Pallant’s excellent article for all the details.