PA-RISC Operating Systems
Many operating systems have been available over the years for PA-RISC computers. Most of them are either commercial Unix or derivates and open source projects with different designs ported to and developed specifically for PA-RISC. An article details the history of PA-RISC operating systems chronologically and more in-depth.
Commercial
The main operating system for PA-RISC was HP-UX, the native Unix for HP 9000 computers sold by HP, in parallel to more niche products for transactions and real-time markets – MPE/iX and HP-RT. Next to these, a slew of other, specialized systems were commercially ported to PA-RISC.
- HP-UX: HP’s main commercial Unix operating system for HP 9000 PA-RISC workstations and servers. The 1996-vintage HP-UX 10.20 has the broadest support for both HP 9000 700 workstations and HP 9000 800 servers, the newer HP-UX 11i releases from the 2000s run on most PA-RISC 1.1, 2.0 and Itanium 2 computers from HP.
- NeXTSTEP: NeXT›s commercial Mach-based operating system for PA-RISC: Microkernel plus Unix userland and modern GUI with support for 32-bit PA-RISC in Version 3.3 in 1994.
- MPE/iX: HP business real-time operating system, used in HP 3000 mainframes on PA-RISC. Not covered here – for more information see hpmuseum.net and Bob Green.
- HP-RT: HP real-time operating system for HP 9000 VME workstations and instrumentation computers, apparently based on LynxOS.
- Convex SPP/UX: Heavily modified Mach-based operating system for the Convex and HP Exemplar SPP PA-RISC mainframes.
- Stratus FTX: System V Unix from Stratus, and Stratos VOS, a transaction-processing oriented system, for the fault-tolerant Stratus Continuum PA-RISC servers.
- Clones and OEMs: Some third-party PA-RISC OEMs in Asia licensed HP-UX or developed their own OS – like Hitachi with HI-UX/WE2 and HI-UX/MPP or Samsung with SS-UX (?).
Open source
Several open source operating systems are available for PA-RISC, having been developed in the early 2000s with proper, mostly stable hardware and software support since then.
- Linux: PA-RISC support was included in mainstream Linux kernels during the 2000s and shipped with Debian and Gentoo distributions as official ports. During the 2010s support declined and development was scaled back, available as part of Debian-ports since 2014.
- OpenBSD/hppa: Open source BSD Unix-like operating system ported to HP PA-RISC computers focused on 32-bit workstations and some 64-bit models running in 32-bit mode.
- NetBSD/hppa: Free, open source Unix-like operating system, and supports PA-RISC computers since around 2005, called NetBSD/hp700 earlier and based on OpenBSD.
- QEMU: The popular open source machine emulator supports PA-RISC in stable version 7.1.0 emulating a B160L workstation, supports running HP-UX, BSD, NextSTEP and Linux
Research and Development
PA-RISC was used for many research projects in the era of the late-80s to the mid-90s, when microkernel research was popular. Many projects were based on Mach or leaned on it, at various places lile HP, Open Group (OSF) and the University of Utah:
- MkLinux: a research project from the mid-1990s by the Open Group/OSF to port a Linux kernel onto a Mach microkernel, based on the MK-PA OSF/1 port to PA-RISC.
- HPBSD from the University of Utah which was a late-1980s port of 4.3BSD and later 4.4BSD to early 800s servers and 700s workstations.
- Mach: Several ports of the Mach microkernel were done during the early 1990s, with HP Tut porting Mach 2.0 and the University of Utah both Mach 3 and Mach 4 Lites.
- OSF/1: Porting efforts for OSF/1, the Unix operating alliance of DEC, IBM, HP and others to compete with AT&T/Sun System V Unix, started around 1990 with HP OSF/1 and MK-PA in the mid-1990s from OSF RI Open Group Research Institute.
Of these MkLinux and Mach 4/Lites were publically available, the others required licenses for commercial or NDA source code they contained. The later Linux and BSD ports made heavy use of their codebase and developments.
Oddballs: A few corporate development projects were pursued for commercial operating systems over the years. Reportedly HP developed a prototype port of Microsoft Windows NT to PA-RISC in 1993 resulting in NT running on a 712 workstation. In the same timeframe, sources mention a two-year effort to port the Novell NetWare operating system to PA-RISC, which HP quit in 1994. And an era later, there was apparently a prototype port of HP-UX to x86 in the 2010s (!) when the future of HP-UX and Itanium was in doubt after PA-RISC was gone.
Support overview
Approximate support matrix for various operating systems on the HP 9000 PA-RISC series’.
| OS | 700s | 740s | 800s | A | B | C | D | E | FGHI | J | K | L | N | R | rp | rx | SD | T | V |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| HP-UX 9 | 📘 | ⚙ | 📘 | ⚙ | ⚙ | 📘 | 📘 | ⚙ | ⚙ | ⚙ | |||||||||
| HP-UX 10.20 | 📘 | 📘 | 📘 | ⚙ | ⚙ | 📘 | 📘 | 📘 | 📘 | 📘 | 📘 | 📘 | 📘 | ||||||
| HP-UX 11.00 | ⚙ | ⚙ | 📘 | 📘 | 📘 | 📘 | 📘 | 📘 | 📘 | 📘 | 📘 | ⚙ | ⚙ | 📘 | 📘 | 📘 | |||
| HP-UX 11i v1 | ⚙ | ⚙ | ⚙ | 📘 | 📘 | 📘 | 📘 | 📘 | ⚙ | 📘 | 📘 | 📘 | 📘 | 📘 | 📘 | 📘 | 📘 | 📘 | |
| HP-UX 11i v2 | ⚙ | 📘 | 📘 | 📘 | 📘 | 📘 | |||||||||||||
| HP-UX 11i v3 | 📘 | 📘 | 📘 | 📘 | |||||||||||||||
| Linux | 📘 | 📘 | 📘 | 📘 | 📘 | 📘 | ⚙ | 📘 | 📘 | 📘 | 📘 | ⚙ | ⚙ | ⚙ | |||||
| OpenBSD | 📘 | 📘 | ⚙ | 📘 | ⚙ | ⚙ | ⚙ | ⚙ | |||||||||||
| NetBSD | 📘 | 📘 | ⚙ | 📘 | ⚙ | ⚙ | ⚙ | ⚙ | ⚙ | ||||||||||
| NeXTSTEP | ⚙ | ||||||||||||||||||
| Mach 3 | ⚙ | ||||||||||||||||||
| Mach 4 | ⚙ | ||||||||||||||||||
| MkLinux | ⚙ | ⚙ | |||||||||||||||||
| OSF/1 | ⚙ | ||||||||||||||||||
| MK-PA | 📘 | ⚙ | |||||||||||||||||
| HP-BSD | 📘 | ⚙ |