PA-RISC Operating Systems History
Overview
Many operating systems and platforms were developed for PA-RISC computers since its inception in 1986. PA-RISC was designed as Unix platform but used in many more commercial, research and later open source systems.
PA-RISC Unix history started in 1986 with early commercial HP Unix — HP-UX for PA-RISC, which is still (somewhat) shipped today. Several other Unix commercial products from HP and other PA-RISC vendors were developed over the years.
Often used for research and development, PA-RISC was part of many academic projects, often based on Mach and BSD kernels and Unix-like operating systems. PA-RISC Open Source is based on these research projects, with the Linux and OpenBSD and then NetBSD port building on their codebases.
| Unix on PA-RISC | Open source on PA-RISC | Research on PA-RISC | |||
|---|---|---|---|---|---|
| History of Unix on PA-RISC | History of Linux and BSD | History of Mach on PA-RISC | |||
|
HP-UX 1.0 to 11i NeXTSTEP 3.3 Convex SPP/UX Stratus FTX PRO: OEM Unixes |
1986‑2007 1994 1993-1999 1995‑2005? 1990s |
Linux on PA-RISC OpenBSD on hppa NetBSD on hp700 QEMU |
1998-now 1998-now 2001-now |
HP Tut HP OSF/1 Utah HPBSD Utah Mach3/Mach4 OSF/1 MK-PA OSF MkLinux |
1988-1989 1990-1991 1989-1993 1991-1996 1994-1996 1997 |
Unix: HP-UX and others
Unix was the standard operating system choice for PA-RISC computer and the main target for PA-RISC while developing it. HP 9000 were dedicated Unix servers and then workstations. Most operating systems for PA-RISC were either Unix implementations or variants of it.
HP developed and ported HP-UX, its commercial Unix offering, to PA-RISC very early on. Closely based on BSD Unix, HP-UX later on moved towards System V. Many of the Asian HP PA-RISC OEMs and clones also used HP-UX variants or own Unix implementations.
Another commercial, Unix-like operating system was NeXTSTEP, ported to PA-RISC during the 1990s, in parallel to other developmental ports of various commercial systems.
The plethora of research projects of the 1990s also used Mach microkernel and Unix-like systems, as did the 2000s open source (OSS) projects.
HP-UX on PA-RISC
The story of HP-UX Unix began before PA-RISC with versions for the early HP 9000 lineup — the HP FOCUS systems. From the late 1980s on, HP-UX was available on the first PA-RISC server computers (800s), with HP-UX 1.0 or 2.0 the first release on PA-RISC in 1986 or 1987.
Many updates soon followed, even though versioning was a bit complicated during that sparsely documented time. In the 1980s, another HP-UX was released with 3.0, followed by HP-UX 7.0 in 1990. The first HP Unix release for both 800 Series servers and the new 700 Series workstation was HP-UX 8.0, followed by 9.0 from the early 1990s, still strongly BSD-based. Releases were still not unified for 700 and 800 computers, with different minor releases specific to both.
The new HP-UX 10 was released a few years later in 1995, delayed for a year due to technical bugs. It was followed in quick sucession by HP-UX 10.10 (mostly ignored), 10.20 and 10.30. Due to feared Y2K issues in earlier versions, HP made HP-UX 10.20 available free of charge for HP 9000 owners for a while. A server-only 10.30 released followed in 1997, as were many Additional Core Enhancements (ACEs), that added workstation hardware support to HP-UX 10.20.
The modernized HP-UX 11.0 was released soon after, starting in 1997, with a true 64-bit kernel
with full 64-bit support for 64-bit computers but still support for many 32-bit PA-RISC systems.
There was supposedly scant support for workstations in the original 11.00 release that was developed by the HP Server division – to be added later with the EP and ACE in 1998 and 1999.
The focus of HP-UX shifted with 11i to the newer lettered
(A-Class, B-Class) and rp/rx 64-bit and Itanium servers.
HP started developing the HP-UX kernel to support PA-RISC and Itanium already beginning in 1997, and apparently together with NEC and Hitachi, old PA-RISC co-conspirators.
HP-UX 11i v2 from 2003 then integrated PA-RISC and Itanium into a single operating system stream while HP-UX was focused more and more on specialized server roles – and stopped supporting most older
PA-RISC workstations and 32-bit servers too.
In the late 2000s, HP ported HP-UX in an internal project to Intel x86 as a hedge during the architecture and operating systems consolidation of that decade. Porting target was a HP development system with 16 Intel CPUs on four mainboards. Development was stopped soon after, as HP committed to HP-UX on IA64 and Windows.
NeXTSTEP on PA-RISC
NeXTSTEP on PA-RISC was a commercial operating system based on Mach and BSD, with an Unix userland and modern GUI.
Introduced in 1989, NeXTSTEP originally supported custom NeXT computers (black
hardware, based on Motorola 68000) in the first few releases and pioneered many modern computer technologies such as the first web browser, UI concepts and an appstore.
NeXTSTEP releases 1.0/0.9 to 3.0 in 1992 only supported black NeXT hardware, with NeXTSTEP 3.1, support for white
Intel i386 hardware was added to broaden the supported user base.
For NeXTSTEP 3.3 the decision was made to support new RISC architectures: PA-RISC and SPARC.
NeXTSTEP was ported to PA-RISC with version 3.3, released in 1994.
NeXTSTEP/hppa was developed specifically for the HP 9000 712 pizzabox workstation, support by HP engineers who worked on the NeXTSTEP kernel.
Applications were supported through fat
binaries, which supported multiple architectures on NeXTSTEP.
Support for PA-RISC in NeXTSTEP was only brief and limited to a select set of 32-bit HP 9000 workstations in version 3.3, which was removed in the follow-on OPENSTEP 4.0.
NeXT and NeXTSTEP, while revolutionary in aspects, did not have much commercial success. OPENSTEP was supported until the late 1990s, which also included development of OPENSTEP APIs for Windows (NT), and a later acquisition by Apple. NeXTSTEP ideas and technologies lived on in Apple MacOS.
For the 1990s, NeXTSTEP on HP 9000 712 workstations was a rather unique and modern operating system experience compared to other Unix and RISC systems.
Other Unix
There were a few other notable operating systems ported to PA-RISC. HP’s own MPE business mainframe operating system was ported from the HP 3000 CISC platform to PA-RISC with MPE/XL and MPE/iX, with several releases from 1988 to 2002.
Several third-party Unix operating systems for PA-RISC mainframes were developed by companies for their own computers. This includes Convex SPP/UX, a heavily modified Mach-based operating system familiar to HP-UX for Exemplar SPP mainframes. Fault-tolerant Continuum servers from Stratus were also shipped with Unix, Stratus FTX, a System V Unix, or Stratos VOS, a transaction-processing oriented system.
In the mid-1990s, as part of the Precision RISC Organisation PA-RISC consortium, some Asian PA-RISC OEMs started selling their own PA-RISC computers. These either made use of licensed HP-UX versions or their own custom developed operating systems – like Hitachi with HI-UX/WE2 and HI-UX/MPP or Samsung with SS-UX.
Even other commercial
Besides well known commercial systems and research projects, some interesting operating systems were ported to PA-RISC. Forgotten since, Windows NT and NetWare were ported to PA-RISC in the 1990s as development projects.
Another PA-RISC operating system by HP was HP-RT, a real-time operating system geared towards instrumentation use cases on HP 9000 740 series VME workstations that had a short-ish lifespan between 1993 and 1997, when customers have migrated to new solutions and platforms more rapidly than anticipated.
Open Source: Linux and BSD
Open source operating systems on PA-RISC became popular through the mid-1990s Mach research ports, which laid the groundwork for more modern and complete open source systems. Mainstream Linux and OpenBSD both started around 1998 to port their respective systems to PA-RISC, and made use of Mach 4 for PA-RISC sources.
HP soon supported the PA-RISC Linux port and made documentation public. Linux on PA-RISC was integrated into the mainline 2.3 kernel in the early 2000s, followed by stable OpenBSD releases. PA-RISC Linux shipped in official Linux distributions, but has been scaled back slightly during the 2010s to be an Debian Port.
Linux on PA-RISC
A native Linux port to PA-RISC was started in 1999 and gained momentum when HP started helping with equipment and documentation in 1999. The main Linux port quickly superseded the earlier Mach-based MkLinux. Because of HP’s assistance, the machines targeted at that time were newer than what other ports supported, like the A180, B180 and 64-bit PA 2.0 systems.
PA-RISC support was included in the mainstream kernel, and shipped with Debian and Gentoo distributions as official ports. During the 2010s however, support declined and development was scaled back, resulting in the eventual removal of PA-RISC from official distributions. PA-RISC Linux still has the broadest support for systems and hardware from the current open source efforts.
Development
In the late 1990s, PA-RISC was the last big
RISC/Unix architecture without a proper Linux port, besides the limited Mach-based MkLinux.
This had multiple reasons – PA-RISC systems were not widely used in academia but had a stronger market share in the technical and industrial world, from which they did no escape for a longer time than others.
HP only reluctantly released technical documentation on their systems to the public in those times, which limited interest in and progress of development efforts.
Slow progress was made in 1999 with the initial start of the original Linux kernel on PA-RISC, as there was growing interest in these machines when more made their way into the second-hand market, and finally more documentation was released.
The Puffin Group
Early work on PA-RISC Linux started in 1999 with the help of The Puffin Group, which later employed several kernel and toolchain developers. Development was at first directed towards 32-bit systems; later on, with the help of HP, more modern machines were made available to developers, resulting in better hardware and 64-bit support.
Puffin Group developed much of the initial PA-RISC compiler and tool chain work.
HP support
In late 1999, HP started supporting and sponsoring PA-RISC Linux and the Puffin Group, in parallel to its Itanium (ia64) Linux undertakings. Earlier ports like Mach and MkLinux did not support newer 64-bit PA-RISC 2.0 computers, and had limited support for only SOM, not ELF binaries.
HP supported the port with developers, code, opening up PA-RISC documentation and sponsoring actual HP 9000 computers. Several important parts of the Linux kernel PA-RISC support were written by HP employees in the project. HP’s support activites were channeled through the new Open Source Solutions Operation unit.
HP distributed HP 9000 PA-RISC computers to developer groups – there were at least HP 9000 A180 and A400 servers used for development. Most PA-RISC work was integrated around 2001 into Linux 2.3 with the majority committed into Linux 2.4, which booted. Stable support depended on solid PA-RISC support in gcc compiler and toolchain, which was added in gcc 2.95.
PA-RISC Linux sponsoring and organizational affiliations changed multiple times after that. HP and developer involvement fluctuated since then, but the port reached a stable state in the late 2000s and Linux distributions like Debian started to pick PA-RISC into their ports tree.
ESIEE
Contributed by Thibaut Varene
The PA-RISC Linux port effort started at the French network of graduate schools ESIEE (École Supérieure d'Ingénieurs en Électrotechnique et Électronique) in December 1999, with Thierry Simonnet, who was then managing the General IT Resources Service at ESIEE getting involved in the early stages of the port. In 2000, Simonnet decided to get students involved and started a case study as part of their school curriculum. The study was conducted in parallel by HP Labs, who sponsored the effort of the school, being a long time partner. This enabled the students to acquire skills, the study was completed in 2001 and presented at Linux Expo in Paris and at the Debian 1 Conference in Bordeaux, France.
With its increasing success, the initial case study spawned into a larger project that was open to students on their free time or as part of their classes, and more joined what was to be called the PATeam. From 2001 to the end of 2003, the team has been very active, doing PA-RISC development in the Linux kernel with writing drivers and improving overall stability. In 2004 and thereafter, ESIEE gradually reduced its support for the project.
OpenBSD and NetBSD on hppa
Work on an OpenBSD port to PA-RISC, OpenBSD/hppa, was started by the late Michael Shalayeff around 1999 in NYC. It was based on information and code from previous Mach porting efforts Lites/HPPA and MkLinux.
The first more or less complete OpenBSD/hppa release was version 3.5, albeit still with limitations many unsupported machines and I/O devices. PA-RISC has since been supported in OpenBSD on most 32-bit workstation, some 64-bit workstations and some servers. An OpenBSD/hppa64 port to support PA-RISC 2.0 computers running in 64-bit mode was started in 2007, but was discontinued after 2016.
NetBSD/hppa another free, open source Unix-like operating system, supports PA-RISC computers since 2005, called NetBSD/hp700 until the 7.0 release, as a Tier II
port.
The port focuses on 32-bit PA-RISC 1.1 computers and 64-bit PA-RISC 2.0 systems in 32-bit.
The current effort is largely based on Michael Shalayeff’s work on the
OpenBSD/hppa kernel from 2004 to 2005 and updated OpenBSD code later on.
Research: Mach and OSF
As soon as PA-RISC was released in the late 1980s, academic and industrial research projects started operating systems ports to PA-RISC. Several other operating systems have been ported to the PA-RISC platform over the time between the late 1980s and late 1990s. Most of them only reached development state and have long been unmaintained. Documentation is rare, some of it only in archives.
HPBSD on HPPA
The premier PA-RISC research system was HPBSD from the University of Utah, a port of 4.3BSD and later 4.4BSD to early HP 9000 800 servers and 700 workstations. HPBSD was born on 68k-based systems in 1987 when Mike Hibler started a port of 4.3BSD to HP 9000/320 and 350 workstations at the University of Utah. Major development lasted until about 1991 with the final addition of Motorola 68040 support.
In 1989, Jeff Forys started work on a HP 9000/800 port based on the hybrid HP-UX/Mach kernel called HP Tut done as an experiment at HP Labs. By 1990, HPBSD was running on an 9000/835 and later that year solidly on PA-RISC. For a short period of time in 1989-90, Mt Xinu also worked on the PA-RISC port and produced the first usable part of it, the boot loader, late in 1989. HPBSD used this boot loader.
In 1990 another Mach project was spun off of HPBSD — the Mach 3/UX single server port for the 9000/835 sponsored by HP and primarily done by Bob Wheeler. Starting in May 1991, Leigh Stoller ported HPBSD to the HP 9000/720 workstation, after which support for PA-RISC 1.0 and the 9000/800 platform was dropped.
The last major development to HPBSD was the addition of the 4.4BSD kernel filesystem and networking code and the 4.4BSD ANSI-compliant C library. Jeff Forys started this in 1992 and by 1993 all of the University of Utah HPBSD machines had been converted. This version was known as HPBSD 2.0. Since this merge included the NFS implementation done by Rick Macklem, all Sun-encumbered code could be eliminated.
In April 1993, a semi-formal release of HPBSD 2.0 was made to the 2-3 sites which had the necessary agreements with HP that were necessary to obtain HPBSD PA-RISC. After that, active development of HPBSD had pretty much stopped. As of Summer 1999, there were less than ten HPBSD machines left. The last efforts were HP-UX compatibility 10.20 for the JDK and a 3Com EISA 100 Mbit ethernet driver.
Taken from the original Utah webpage, modified, with permission from Mike Hibler
Mach Microkernel on PA-RISC
Several ports of the Mach microkernel were undertaken during the early 1990s, with HP Tut using Mach 2.0 and the University of Utah trying Mach 3 and Mach 4. Porting efforts for OSF/1, the alliance Unix operating system from DEC, IBM, HP and others to compete with AT&T and Sun’s System V Unix, started around 1990.
The first Mach 3 port to PA-RISC was Mach 3/UX from the University of Utah around 1991, one of the first various Mach microkernel ports to PA-RISC. This project targeted a proper port of Mach to PA-RISC on HP 9000/835 servers, where the HP-internal HP Tut somehow failed. Mach 3/UX never got very far, but code wound up later in Mach 4/Lites and probably MK-PA from OSF.
The University of Utah Flux Research Group ported the original Mach microkernel with a 4.4BSD-Lites server around 1994 to the PA-RISC architecture, based on the work of the Mach 3/UX project, and called it Mach 4/Lites. There was not much support provided and few enhancements made over the years, and it was quickly discontinued in favor of other projects both at Utah University and elsewhere, for example the MkLinux port. The project was seen from the beginning not as a complete operating system but rather as a snapshot for developers.
The operating system kernel is based on a Mach kernel, derived from CMU’s (Carnegie Mellon University) MK83 release, and is loosely referred to as Mach 4. It contains some initial work done at Utah as part of the ARPA-funded Fast and Flexible Mach Systems work. In particular it contains a prototype implementation of migrating threads and a basic framework for signature-based remote procedure calls, a fundamental component of the presentation/interface work. None of these features is used either by the Lites server or within the kernel itself.
Also included is additional code never integrated into Mach 4, that was part of Utah’s earlier Mach 3/UX and HPBSD ports or HP OSF/1. The former includes bus configuration and rudimentary device drivers for the CIO bus based workstations and servers as well as a remote kernel/task debugging facility developed by Convex. The latter includes some basic EISA support and alternative LAN drivers.
Taken from the original Utah webpage, modified, with permission from Mike Hibler
OSF/1 Unix on PA-RISC
HP itself ported OSF/1 to PA-RISC, which was never widely available commercially. This port was superseded in the mid-1990s by the OSF RI Open Group Research Institute with several releases of MK-PA. All of the Mach ports were never really used widely as production systems, but formed the basis for other research projects and later the BSD and Linux ports.
The OSF Open Group Research Institute ported OSF/1 to PA-RISC in the mid-1990s as research project, focusing on 32-bit HP 9000/700 workstations and servers. Porting was supported by HP in some way. Research releases were MK6.0-PA in 1994, MK6.3-PA in July 1995 and MK7-PA and MK7.2-PA in 1996. OSF MK-PA was never released widely, but used for research purposes, including ARPA projects (including radar tracking). Obtaining MK-PA from OSF RI required an OSF/1 source license.
MK-PA as research project wanted to demonstrate PA-RISC as OSF RI reference platform, performance parity between HP-UX and MK based systems, HP-UX binary compatibility, high-speed networking capability.
The version of Mach 3 used by the OSF porting effort contained several of the Mach 4 enhancements of the University of Utah and probably used parts of the Mach 3/UX PA-RISC codebase. Parts of the MK-PA port itself were then used as base of the OSF port of Linux onto OSF Mach, MkLinux, which in turn was the base of several other PA-RISC porting efforts in the 2000s.
MkLinux on PA-RISC
Early Linux support on PA-RISC built upon the MkLinux research project from the mid-1990s by the Open Group/OSF, that ported a Linux kernel onto a Mach microkernel, which in turn built on the previous MK-PA OSF/1 port to PA-RISC.
MkLinux was a 1990s project led by Apple and Open Group Research Institute to port Linux hosted on top of a Mach microkernel (pmk1.1) to run an Apple PowerPC computers like PowerBooks. A research project between Open Group and OSF ported that system later to PA-RISC computers, supported by HP, with first PA-RISC development releases were in 1997.
MkLinux was the first free operating system that truly worked on PA-RISC hardware, in contrast to the various Mach ports, which suffered from unfinished development and a lot of bugs on PA-RISC. MkLinux on PA-RISC built on the previous OSF/1 MK-PA port and integrated parts from the PA-RISC kernel sources from the Utah University, including Mach 3/UX and Mach 4/Lites. MkLinux improved the underlying OSF PA-RISC/Mach kernel from MK-PA put a Linux 2.0 kernel as server personality on top, replacing BSD/Lites from the previous efforts. Included were X11R6 patches, the GNU ELF compiler and debugger and complete /usr and /var directories.
Other Microkernel on PA-RISC
An internal HP research project was HP Tut from around 1988-89 to port HP-UX onto a Mach microkernel. The project apparently never suceeded far and moved on to merging parts of Mach 2.0 under HP-UX 2.0 to get something close to resembling Mach on PA-RISC. HP Tut was the basis for various other porting efforts and PA-RISC research projects within and outside of HP.
Another micro-kernel operating system was Chorus by INRIA with a development port to PA-RISC done in 1990-1991 at the Oregon Graduate Institute (OGI) for PA-RISC 1.0 HP 9000/834 servers (workstations
).
This port was based on Chorus v3.3/MiX v3.2.
Hardware support and functionality was limited, with apparently no network interfaces or disk devices
supported and console I/O depending on PDC and IODC routines.
Code from various earlier projects was used, including from HP-UX 2.0 and HP Tut, HP-UX on 2.0 Mach. A later project ported Chorus v3.4 to the 9000/720 workstation a popular target for OS/Unix porting efforts at that time.
Timeline
| Year | HP-UX | Linux | OpenBSD | NetBSD | HPBSD | Mach 3 | Mach 4 | OSF/1 | MkLinux | NeXTSTEP |
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Further reading
- For more technical information see the PA-RISC Operating Systems page, with details on release timelines and introduction dates on the PA-RISC Timeline.
- PA-RISC Linux Project History, PA-RISC Linux Wiki, OLD NEWS, 2024
- HPBSD: Utah’s 4.3bsd port for HP9000 series machines Original homepage of the HPBSD project. Mike Hibler (July 1999: University of Utah)
- The Utah PA-RISC Code Snapshot Original webpage of the project. Mike Hibler (2002: University of Utah)
- MK-PA: An HP-UX compatible microkernel based Operating System, The Open Group (1998) archive.org
- MK-PA Project Update, James Loveluck (1996: The Open Group) archive.org
- OSF MK 7.2, OSF RI (1997: archive.org, accessed February 2018)
- HEWLETT-PACKARD PUTS OSF/1 ON HOLD AS IT MERGES DOMAIN WITH HP-UX, Computer Business Review, March 22, 1992
- MkLinux - Linux on the OSF Microkernel, The Open Group (1997, archived by CIRR 1999, current mirror MkLinux.org accessed 2022)
- MkLinux for HP PA-RISC, The Open Group (1997, archived by CIRR 1999, current mirror MkLinux.org accessed 2022)
- Release Notes for MkLinux on HP PA-RISC Descriptions on MkLinux and extensive installation instructions. The Open Group (1997, archived by CIRR 1999, current mirror MkLinux.org accessed 2022)
- Sun and NeXT throw open the doors to industry-standard object-oriented computing and Technical Implications, NeXTWORLD 1993 February (nextcomputers.org 2023)