Emulating HP-UX using QEMU

While we’re out here raising funds to make me daily-drive HP-UX 11i v1 – we’re at 59% of the goal, so I’m starting to prepare for the pain – it seems you can actually run older versions, HP-UX 10.20 and 11.00 to be specific, in a virtual machine using QEMU.

QEMU is an open source computer emulation and virtualization software, first released in 2003 by Fabrice Bellard. It supports many different computer systems and includes support for many RISC architectures besides x86. PA-RISC emulation has been included in QEMU since 2018.

QEMU emulates a complete computer in software without the need for specific virtualization hardware. With QEMU, a full HP Visualize B160L and C3700 workstation can be emulated to run PA-RISC operating systems like HP-UX Unix and compatible applications.
↫ Paul Weissman at OpenPA

The emulation is complete enough that it can run X11 and CDE, and you can choose between emulating 32bit PA-RISC of 64bit PA-RISC. Devices and peripherals support is a bit of a mixed bag, with things like USB being only partially supported, and audio not working at all since an audio chip commonly found in PA-RISC workstations isn’t supported either. A number of SCSCI and networking devices found on HP’s workstations aren’t supported either, and a few chipsets don’t work either.

As far as operating system support goes, you can run HP-UX 10.20, HP-UX 11.00, Linux, and NetBSD. Newer (11i v1 and later) and older (9.07 and 9.05) versions of HP-UX don’t work, and neither does NeXTSTEP 3.3. Some of these issues probably stem from missing QEMU drivers, others from a lack of testing; PA-RISC is, after all, not one of the most popular of the dead UNIX architectures, with things like SPARC and MIPS usually taking most of the spotlight.

Absolutely nothing beats running operating systems on the bare metal they’re designed for, but with PA-RISC hardware becoming ever harder to obtain, it makes sense for emulation efforts to pick up speed so more people can explore HP-UX. I’m weirdly into HP-UX, despite its reputation as a difficult platform to work with, so I personally really want actual hardware, but for most of you, getting HP-UX 11i to work properly on QEMU is most likely the only way you will ever experience this commercial UNIX.