Editing OpenVMS (section)

===Port to Intel Itanium===
[[Image:OpenVMS logo Swoosh 30 lg.jpg|thumb|"Swoosh" logo used by HP for OpenVMS]]

In 2001, prior to its acquisition by [[Hewlett-Packard]], [[Compaq]] announced the port of OpenVMS to the [[Intel]] [[Itanium]] architecture.<ref>{{cite web|url=http://h71000.www7.hp.com/openvmstimes/openvmstimes.pdf|title=Compaq OpenVMS Times|date=January 2002|archive-url=https://web.archive.org/web/20060302213751/http://h71000.www7.hp.com/openvmstimes/openvmstimes.pdf|archive-date=March 2, 2006|url-status=dead}}</ref> The Itanium port was the result of Compaq's decision to discontinue future development of the Alpha architecture in favour of adopting the then-new Itanium architecture.<ref>{{cite web|url=https://www.theregister.com/2001/06/25/farewell_then_alpha_hello_compaq/|title=Farewell then, Alpha – Hello, Compaq the Box Shifter
|author=Andrew Orlowski|date=June 25, 2001|access-date=December 21, 2020|website=theregister.com}}</ref> The porting began in late 2001, and the first boot on took place on January 31, 2003.<ref>{{cite newsgroup|url=https://groups.google.com/g/comp.os.vms/c/alWtue7YLUw/m/x1_GVv1eFfEJ|title=OpenVMS Boots on Itanium on Friday Jan 31|date=January 31, 2003|access-date=December 21, 2020|author=Sue Skonetski|newsgroup=comp.os.vms}}</ref> The first boot consisted of booting a minimal system configuration on a [[List of Hewlett-Packard products#Itanium based|HP i2000]] workstation, logging in as the <code>SYSTEM</code> user, and running the <code>DIRECTORY</code> command. The Itanium port of OpenVMS supports specific models and configurations of [[HPE Integrity Servers]].<ref name="vms-8.4-spd" /> The Itanium releases were originally named ''HP OpenVMS Industry Standard 64 for Integrity Servers'', although the names ''OpenVMS I64'' or ''OpenVMS for Integrity Servers'' are more commonly used.<ref>{{cite web|url=https://vmssoftware.com/docs/ig_bvbv.pdf|title=HP C Installation Guide for OpenVMS Industry Standard 64 Systems|date=June 2007|publisher=HP|access-date=March 2, 2021}}</ref>

The Itanium port was accomplished using source code maintained in common within the OpenVMS Alpha source code library, with the addition of conditional code and additional modules where changes specific to Itanium were required.<ref name="ia64-port" /> This required certain architectural dependencies of OpenVMS to be replaced, or emulated in software. Some of the changes included using the [[Extensible Firmware Interface]] (EFI) to boot the operating system,<ref>{{cite web|url=http://www.decus.de/slides/sy2005/06_04/2g04.pdf|title=OpenVMS Integrity Boot Environment|date=2005|access-date=December 21, 2020|author=Thomas Siebold|website=decus.de}}</ref> reimplementing the functionality previously provided by Alpha PALcode inside the kernel,<ref name="swis" /> using new executable file formats ([[Executable and Linkable Format]] and [[DWARF]]),<ref>{{cite web|url=http://www.hp-user-society.de/events/alphamigration/vortraege/porting_openvms_applications_to_itanium.pdf|title=Porting OpenVMS Applications to Itanium|access-date=December 21, 2020|website=hp-user-society.de|date=2005|author=Gaitan D’Antoni}}</ref> and adopting [[IEEE 754]] as the default floating point format.<ref>{{cite web|url=http://www.decus.de/events/alphamigration/vortraege/i64-floating-pt-wp.pdf|title=OpenVMS floating-point arithmetic on the Intel Itanium architecture|website=decus.de|access-date=December 21, 2020|date=2003}}</ref>

As with the VAX to Alpha port, a binary translator for Alpha to Itanium was made available, allowing user-mode OpenVMS Alpha software to be ported to Itanium in situations where it was not possible to recompile the source code. This translator is known as the ''Alpha Environment Software Translator'' (AEST), and it also supported translating VAX executables which had already been translated with VEST.<ref>{{cite web|url=http://www.decus.de/slides/sy2005/06_04/2g05.pdf|access-date=December 21, 2020|website=decus.de|date=2005|title=OpenVMS Moving Custom Code|author=Thomas Siebold}}</ref>

Two pre-production releases, OpenVMS I64 V8.0 and V8.1, were available on June 30, 2003, and on December 18, 2003. These releases were intended for HP organizations and third-party vendors involved with porting software packages to OpenVMS I64. The first production release, V8.2, was released in February 2005. V8.2 was also released for Alpha; subsequent V8.x releases of OpenVMS have maintained feature parity between the Alpha and Itanium architectures.<ref>{{cite web|url=http://de.openvms.org/TUD2005/12_Open_VMS_Strategy_Paul_Lacombe.pdf|title=HP OpenVMS Strategy and Futures|author=Paul Lacombe|date=2005|access-date=December 21, 2020|website=de.openvms.org|archive-date=February 7, 2021|archive-url=https://web.archive.org/web/20210207063543/http://de.openvms.org/TUD2005/12_Open_VMS_Strategy_Paul_Lacombe.pdf|url-status=dead}}</ref>