PA-RISC information - since 1999

HP 9000 and PA-RISC Story

HP 9000 was a family of technical servers and workstations produced by HP between the 1980s and 2000s that included a diverse range of Unix computers, based on HP PA-RISC, Itanium and other architectures.

Both RISC and Unix were developed into products during the 1980s, moving from academia via industrial R&D to productization — at a time when much computing was still done on mainframes, minicomputers and time-sharing machines such as DEC PDP, VAX, IBM AS/400 and System/360.

HP 9000 and the PA-RISC series were HP’s new line of products in that fledging market in the early 1980s. This page focuses on this PA-RISC part of that story, divided into four periods from the 1980s to the 2000s that each featured distinct designs.

PA-RISC computer period table
Phase Workstations Servers Mainframes Others
Prelude: Early 1980s Other HP 9000
500 series
Other HP 9000
200, 300 series
Infancy: Late 1980s
Phase I
HP 9000 800
840 to 870, 600
Other HP 9000
Apollo, 400
Growth: 32-bit 1990s
Phase II
HP 9000 700
720-750, 705-725
HP 9000 800
VME industrial
742, 745i, 747i
Third party
Hitachi, NEC (PRO)
Maturity: 1990s heydays
Phase III
HP 9000 700
712 and 715
Visualize workstations
HP 9000 800
Lettered servers
VME industrial
743, 744, 745, 748
SAIC, RDI, Hitachi
Decline: 64-bit 2000s
Phase IV
zx workstations
rp servers
rx servers

This page is an attempt to unify all the different leads and streams of HP 9000 and PA-RISC into a single story, but simplifications were made. For exact release dates of HP 9000 computers and their market entry prices, there is also the PA-RISC Timeline page. A tabular overview of the 200+ HP 9000 PA-RISC systems can be found on the main PA-RISC Computers section that links to pages with more details for individual systems.

The history of PA-RISC processors and HP 9000 system architecture is covered briefly in the PA-RISC Hardware page. Separate articles are dedicated to the history of PA-RISC operating systems as well as the history of PA-RISC information and OpenPA itself.

Prelude to PA-RISC – Early 1980s

The prelude to PA-RISC computers took place during the early to mid-1980s, starting with the 1982 HP FOCUS computers.

In the early 1980s, HP worked on both Unix and RISC development and products. Before PA-RISC, the original HP 9000 series was released with the FOCUS-based 500 series (9020). In parallel, the Motorola 68000 were added as HP Unix workstations.

Other HP 9000

There were a few other computer series offered under the HP 9000 label before PA-RISC computers were released. This includes early Unix platforms from HP based on Motorola m68k CISC processors, the HP FOCUS line that preceeded PA-RISC and the HP 3000 minicomputers, that later switched to PA-RISC.

The HP 9000 200 series were the earliest incarnations of HP Unix platforms based on Motorola 68000, and started life as HP 9826 in 1981, all using the Motorola 68000 processor. Soon followed by other high-end technical desktops, such as the HP 9836, 9816, 9920, 9817 and 9837H, there series was renamed in the early 1980s to HP 9000 200 series, and the individual computers to, for example HP 9000/220 (for the 9920). The 200s also ran versions of HP-UX Unix.

The other series based on Motorola M68k processors was the HP 9000 300 series, sold from the mid-1980s to the early 1990s and also a Unix platform. The 300s had a new, functional design with several distinct boxes for each computer, a design later taken over for the first HP 9000 700s series workstations. The 300 series used Motorola CISC processors from the 68010 up to the -40. Besides HP-UX, the 300 series were supported by a variety of BSD operating systems from the 1980s well into the 2010s, including the mythical 4.4BSD and the OpenBSD/hp300 and NetBSD/hp300 siblings.

HP 9000 500: The 520 computers were the early-1980s predecessors of PA-RISC and started the HP 9000 series. They were based on a proprietary HP 32-bit processor — the HP FOCUS. First released in 1982, the HP 9000/520, originally 9020, was quickly followed by the HP 9000 530, 540 and 550 computers. Operating system support was limited to HP-UX which on HP FOCUS allegedly was the first commercial Unix supporting a multi-processor, multi-user system.

The HP 3000 line were the HP business minicomputers, first released in 1972, with their own operating system MPE, application stack and distinct customer base.. For more information read the 3000-MPE (Software) article from and The History of the HP 3000 from Bob Green.

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Infancy (I) – Late 1980s

The infancy of PA-RISC took place between 1986 and the late 1980s with first PA-RISC products.

HP moved into the fledging microcomputer market in the late 80s with several differently positioned platforms. PA-RISC computers of the HP 9000 Series 800 were HP’s RISC entry into that market. The other CISC HP 9000 offerings were sold by HP in parallel for almost a decade. The PA-RISC 9000 800 series were offered as servers initially for business applications, but were quickly adapted for technical and engineering. Several processor, fabrication and systems design were tried by HP in those late-1980s days with the 800s.

Early RISC computers and 800s

The original PA-RISC computers were the HP 9000 800 servers developed by HP in the 1980s and released in late 1980s. They consisted of several computers based on 32-bit PA-RISC 1.0 and 1.1 processors and different designs. System architecture was rather divergent to the 700s workstations with different chipsets, buses and I/O devices. HP 9000 700 series was introduced slightly later than the 800s, with a different, more workstation-centric focus.

Due to their separate system design and usage scenarios, HP 9000 700 and 800 series used different HP-UX Unix versions for a long time, until HP-UX 10.20. Support for the 800 series in open source systems was always limited due to sparse documentation on their architecture. The 800 series PA-RISC servers carried on into the lettered servers of the A/D/K/N-classes that kept a divergent architecture to the 700 and Visualize workstations, focused on multi-user business applications.

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Other HP 9000

Interestingly, before releasing the HP 9000 700, HP bought Apollo, a technical computing market leader of the 80s, with their PRISM (RISC)-based Domain 10000 workstations. Apollo Domain workstations was carried on for a few years under HP/Apollo branding. HP integrated Apollo as their workstation business unit with Apollo co-branding on the HP 9000 RISC workstations for a while but Apollo products and technology were phased out soon after. HP concentrated on its own PA-RISC computers and architecture since.

Related to the HP 9000 300 series from the early 1980s but incorporating technology from the 1989 acquisition of Apollo Computers, the HP 9000 400 series was based on Motorola 68030 and 68040 processors and ran HP-UX and Domain/OS (Apollo Unix). The HP 9000 400 were sold in parallel to PA-RISC computers of the 700 and 800 series in the early 1990s, and were widely supported by BSD and open source operating systems. Many designs, devices and peripherals were shared between the Motorola 68000-based 400 series and the PA-RISC 700 and 800 series, including SGC and EISA buses, SCSI controllers, HP-HIL and HP-IB peripherals and graphics.

From the late 1980s on, HP 3000 moved to the PA-RISC platform and used systems that were closely based on the HP 9000 800 series. HP 3000 used PA-RISC actually earlier than the widely-popular HP 9000 700 workstation series. The first MPE for PA-RISC release was MPE/XL, the last MPE version was MPE/iX with limited Unix support and POSIX compliance. HP 3000 and MPE have been discontinued since.

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Growth (II) – 32-bit 1990s

Much of the growth phase of HP 9000 and PA-RISC happened between 1990 and 1992. HP differentiated its PA-RISC product offering from large main-frame servers to small desktop workstations on Unix.

To round up and segment its offerings, HP released a dedicated PA-RISC workstation line, the HP 9000 700 series. Based on the new, CMOS PA-RISC 1.1 processors, the original workstations consisted of the Snake 720/730/750, smaller systems (705/710) and technical desktops (715/725). They were often used as a platform for Unix-based graphics, engineering and R&D, and slowly became popular for high-end use cases. Some opening up of the tightly-controlled PA-RISC happened with the HP PRO organization and third-party systems.

HP 9000 700 workstations

A large range of PA-RISC workstations was sold by HP with the HP 9000 700 series, from the 1990s on. The 700 series soon became popular 32-bit Unix RISC workstations and used HP’s new processors like the PA-7000, PA-7100 and (later) PA-7100LC.

© Hewlett Packard 1996

At that time, much technical computing centered on Unix and RISC workstations, superseding older CISC computers. The new workstations were often used for CAD, CAM and specialized software for HP-UX or Unix.

HP acquired Apollo Computers around the time, so the Apollo name and technology became part of some workstations, sometimes called HP Apollo 9000.

PA-RISC 700 workstations gained wide popularity in engineering, industrial and academic fields during the 1990s. During that time, PA-RISC with the 700s workstations traded the performance crown of Unix and RISC computers frequently with DEC Alpha architecture. PA-RISC workstations were developed by the HP Workstation Systems Division in Ft. Collins, Colorado, USA.

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HP 9000 800 servers

F/G/H/I-Class: These were the second generation HP 9000 800 servers from the early-1990s. The HP 9000 Nova servers share a similar, distinct 32-bit PA-RISC design. They had wildly diverse configurations for server applications from the small F10 to the large I70.

HP 9000 890: The 890 servers were an early iteration of the T-Class mainframe architecture, with the later T500/T600 being updated sucessors. Even later the basic 890/T-Class system design was discontinued in favor of the more flexible Superdome systems.

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VME and Industrial

The 740s VME-based PA-RISC computers were part of the HP 9000 700 series, sold from the early to late 1990s, used for industrial, scientific and military data measurement and real time control applications. These single-board computers utilized the industrial-grade VME bus for that. Processors included 32-bit PA-RISC PA-7100, PA-7100LC and PA-7300LC with HP LASI and ASP chipsets and some custom VME designs.

© 1997 Hewlett Packard

Operating systems were native HP-UX and HP-RT, the latter for real-time applications, with some supported in Open Source operating systems including Linux and BSD. They were used in a very wide variety of applications for industrial and scientific control and measurement, including by the US military.

HP 74x VME products were discontinued in 2002 as customers have migrated to new solutions and platforms more rapidly than anticipated with end of support between 2003 and 2007.

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Third party

The Precision RISC Organisation (PRO) consortium was formed by HP and Convex in 1992 to promote the PA-RISC architecture. PA-RISC chips and designs were usually not sold to third-parties with licensing and distribution tightly controlled by HP to partners in the PRO.

Some PRO members sold third party PA-RISC computers as OEM or relabeled HP 9000 systems from HP in their markets:

These computers were mostly sold in Japan and Korea, with very limited worldwide distribution. Their vendors soon lost interest in PA-RISC as part of the 2000s general RISC decline.

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Maturity (III) – 1990s heydays

The maturity of PA-RISC was the phase between 1994 to 2000 with many new products offered, from the last 32-bit workstations to new 64-bit PA-RISC 2.0 when HP Unix was (still) very popular.

© Hewlett Packard 2000

Many PA-RISC products were released and the HP Unix/RISC line-up matured during the 1990s, from small PA-RISC desktops to large server cabinets and mainframe-type computers. HP used increasingly complex brands and product groups — HP 9000 700, HP Visualize, HP Integrity with the various lettered workstations and server series A-Class, B-Class, J-Class and so on.

PA-RISC moved from 32-bit to 64-bit with the revamped PA-8000 processors and its subsequent successors up to the Mako PA-8800 with fairly high-powered Unix systems for the niche HP-UX technical and business market. Commodity and mainstream alternatives to RISC and Unix slowly started to appear at the end of that era with Window NT, Linux and faster x86 computers.

HP 9000 700 workstations

Pizzabox 712 and newer 715: PA-RISC computer design was updated in 1994 with the HP 9000/712 and newer 715 workstations, based on the modern, integrated PA-7100LC processor and LASI chipset. The 712 was a revolutionary pizza-box design that offered the advantages of a commercial Unix system on a RISC platform in a very small case (something Apple did a decade later again). Both were used for CAD and graphics, and were popular choiced for Unix and open source development.

The first PA-RISC portable, SAIC Galaxy was developed as part of a military contract (TAC-4) by SAIC. It was based on the HP 9000 712 workstation mainboard, built into a ruggedized case for portable military applications.

Visualize Workstations

From the mid-1990s on, HP sold its PA-RISC workstations with lettered class names: the B-Class, C-Class and J-Class systems, still formally part of the 9000 700 series. Most of them were sold with Visualize branding indicating a focus on their preferred applications and use cases.

© Hewlett Packard 2001

The Visualize workstations were geared towards graphics and engineering applications such as CAD or CAM and often used with HP’s powerful Visualize and Visualize-FX graphics adapters. Processors were almost the whole range of PA-RISC CPUs from 32-bit PA-7200 up to 64-bit PA-8900.

Around 1997, due to competition and a changing market place, HP started aggressively repricing its HP 9000 and Visualize workstations with price drops of more than a third, to compete with Sun Ultra 1 and SGI Indigo2 workstations.

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HP 9000 800 servers

E-Class: These were the third generation HP 9000 800 servers from the mid-1990s. The HP 9000 E-Class were the follow-on of the F/G/H/I-Class servers but based on low-cost PA-7100LC processor and integrated system design in smallish tower cases with the E25 to the E55. These were the last traditionally called HP 9000 800 Series.

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Laptops and Portables

Only three portable PA-RISC workstations were produced during 1990s — all by third-party vendors utilizing HP 9000 workstation designs from that era. First, there was the military-focused SAIC Galaxy 1100 portable from 1994, based on HP 9000/712 workstations and available through the Navy TAC-4 program, a very rare computer almost completely used in the military.

Then at the end of the 90s, there were the RDI PrecisionBooks, true laptops based on C132L workstation designs from HP, which were designed into a military-focused portable system by RDI, later acquired by Tadpole. It did not enjoy widespread success.

In the mid-1990s, Hitachi of Japan designed another PA-RISC portable, the 3050RX/100C for the Japanese market, based on the Hitachi PA/50L processor.

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Lettered servers

In parallel to the workstations, HP 9000 servers were renamed with lettered designators and included a spectrum of different 32- and 64-bit PA-RISC computers. These servers were quite powerful at the time of the 1990s with diverse configurations and designs, from the small A-Class to the mid-size D-Class and cabinet-size K-Class.

Also during that time, the system architecture between 700s workstations and 800s servers began to converge, only to start diverging again in the late-1990s with the Cell and Stretch architectures, when HP moved to hardware virtualization.

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© Hewlett Packard 1997

The label mainframe is used rather broadly here to include all larger HP PA-RISC computers with a large amount of computing resources that were either multi-processor or cluster-type systems. Some were HP’s own development, like the T-Class, an outgrow of the original 800 series servers, and the later Superdome, while others were either co-developed or acquired externally, like the SPP Exemplar architecture from Convex, with which HP partnered as reseller in 1994 before buying them outright in 1995.

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Decline (IV) – 64-bit in the 2000s

HP slowly transitioned to a post-RISC phase in the 2000s, with a long-planned move to VLIW Itanium IA64 for its technical and Unix offerings. The decline of PA-RISC was set in stone much earlier than that, with the mid-1990s joint development of Itanium together with Intel, and decided in the mid-2000s. Beginning in the late 1980s, PA-RISC systems often wore the crown of fastest technical (RISC and Unix) workstations until the heydays of the 90s, albeit at a (boutique) price. PA-RISC was relegated in the 2000s to a niche market with the rp Integrity PA-RISC servers. As a result of a changing market environment, PA-RISC slowly was phased out of the technical HP line-up first for Itanium products and later for mainstream x86 (64-bit) computers.


HP renamed its PA-RISC servers again in the early 2000s into the rp series, and shifted the focus of PA-RISC more towards servers with that move. The rp servers were based on 64-bit PA-RISC processors from the PA-8500 to the PA-8800, all multi-processor. Only the first rp branded systems shared design features with contemporary workstations and older servers, while the rest were new, server-only designs.

With the rp range HP moved its PA-RISC offering closer to the new Itanium architecture, which were called rx. Product and technical design was similar between rp and rx, and the PA-RISC rp moved strongly towards Itanium design with the zx1 chipsets and upgrade paths to IA64 processors. The rp were the last line of PA-RISC servers.

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Around the turn of the century, HP started to offer servers and workstations based on Itanium IA64 technology, a VLIW architecture jointly designed with Intel. System architecture between the PA-RISC rp and IA64 rx servers converged with similar zx1 chipset and Itanium buses. Itanium (the IPF) slowly phased out PA-RISC from HP’s technical and Unix lineup around 2002.

However, this happened at least half a decade later than originally planned – the transition from PA-RISC to Itanium is inevitable, as HP put it. To convince hesitant PA-RISC holdouts to make the move, HP claimed Itanium is really the evolutionary successor to PA-RISC and PA-RISC lives on in the IPF architecture with HP Unix servers reflect our smooth evolutionary philosophy admirably.

This was the end of the PA-RISC platform at HP, which vanished with diminishing market share until the mid-2000s. The process of the long decline of RISC and commercial Unix servers was already underway then, with Unix relegated to special applications and later to high-end, mission-critical servers. HP started withdrawing from Unix workstations before Itanium, but pared down its offering even further with the new CPU architecture.

© Hewlett Packard 2001

Shipments of Itanium workstations ceased two years after release, at the time when Intel moved the x86 architecture to 64-bit. Originally envisaged as an industry-changing architecture, Itanium ended up as alternative to other RISC platforms it was meant to replace, and marked the end-phase of HP Unix and RISC platforms. Support for Itanium on Linux was also ended with Linux 6.7 in 2024.

On a side tangent of history, HP inherited both DEC Alpha RISC and OpenVMS through its acquisition of Compaq in the early 2002, both had been having rivals for HP platforms for decades. After discontinuing DEC Alpha, OpenVMS was to find a new home with the Itanium platform at HP, to which it was ported around 2005 to run on HP rx servers, being the first computers to offer both HP-UX and OpenVMS.

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Large computers in the Mainframe category, which were not really called that anymore, was the last refuge of PA-RISC architecture with the Superdome computers that utilized a similar (Cell) architecture as earlier rp and N-Class servers.

Superdome: The Superdome servers were a completely new design, for up to 64 processors per cabinet. The Superdome Legacy, or white systems, used a Cell crossbar chipset with 64-bit PA-RISC processors, while the newer Superdome sx1000 and sx2000, or black systems, used SX chipsets and a mixture of Itanium 2 processors. They all ran HP-UX and Linux, while the SX models also Windows and OpenVMS.

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HP 9000 started as a family with 500s in 1982, PA-RISC joined with the 840 server in 1986, giving birth to the 800 series of department servers. HP soon started to diversify the Unix and PA-RISC offering, introducing the 700 series workstations, the 740 series VME boards and latter followed in the middle of the 90s by a large range of lettered computers (A-Class, J-Class ...) that were also marketed as Visualize and Integrity, then switching to rp and rx naming.

PA-RISC timeline, - workstation, - server, - rack
Year 500 600 700 740 800 Apollo A B C D E FGHI J K L N R rp rx SD T V
1982 ∆ █
Year 500 600 700 740 800 Apollo A B C D E FGHI J K L N R rp rx SD T V

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The information on this page is based mostly on existing OpenPA content, but also includes new content and interpretation of other sources. Some pieces were sourced from the great HP Computer Museum, but also from news releases, journals or HP Labs communication.

Further reading

Pictures © Hewlett Packard, scans from product brochures, from and

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