Chapter 4 PA-RISC Computer Systems - OpenPA.net

Chapter 1
Introduction
OpenPA is a guide to Hewlett-Packard PA-RISC and IA64 computer systems, architecture and operating
systems. PA-RISC is a computer architecture developed by Hewlett-Packard in the early to
mid-1980s and used in a range of workstations and servers (the HP 9000s). Some systems based on
HP/Intel Itanium IA64 are also covered as descendants of the HP 9000/PA-RISC systems.
This book, now in its second edition, is the offspring of the online project OpenPA.net, a non-commercial
information resource on PA-RISC computers. It is independent of The Hewlett Packard Company.
The online OpenPA.net is a registered serial publication with the ISSN 1866-2757.
Plans for an offline-viewable edition of OpenPA.net for printing-out were first discussed in 2002 but
quickly abandoned for lack of technical feasibility and knowledge. A second attempt in 2006 led to
the First Edition, published in Summer 2006 and completely updated in November 2007 with Release
1.1 of the First Edition. A limited numbered edition was printed and bound in December of that year
(1.2). Much polishing, content additions (about 90 pages) and updates led to the greatly improved
Second Edition in May 2008, quickly followed by 2.1 in October 2008 with more content. Updates
included an improved typeset, much polished TEX usage and much work devoted to tweaking details.
More reformatting, several page removals and text overhaul resulted in the Second Edition 2.2 in Winter
2008/2009, followed by and update with more content in July 2009. The last edition (2.4) was
released three years later, in July 2012, catching up with all changes in between. The process from
the online HTML sources to this PDF is rather long and complicated, with the bulk of the work automated
by helper scripts and programs. The only handrolled parts are this introductory chapter, the
title/preface pages, the main TEX file and several manually formatted tables.
The online version of OpenPA.net was started in 1999 after the author got his first PA-RISC workstation
and could not find any coherent information on HP PA-RISC on the internet. Since other popular
Unix/RISC workstation families were well documented, an effort was started to research and collect
useful information and compile that into an online site as public reference source. The initial support
from HP for the PA-RISC Linux project made many interesting documents about PA-RISC available.
Other open-source operating systems for PA-RISC computers made significant progress as well (primarily
OpenBSD/hppa from Michael Shalayeff). Documentation on most 64-bit PA-RISC computers
(mainly servers, as HP more or less quit producing Unix workstations) and other details on the site
were completed in 2007-2008, with only few rare and unusual PA-RISC systems not covered (including
the Superdome and other supercomputers). In about the same timeframe a range of IA64/Itanium
computers were included in OpenPA.net, spanning all three HP Itanium workstations and a large part
of HP Itanium servers (the rx line).
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