Editing DEC Alpha (section)

{{Short description|64-bit RISC instruction set architecture}}
{{Infobox CPU architecture
| name       = Alpha
| image      = DEC Alpha Generation logo.svg
| caption    = "Alpha Generation" logo used by Digital
| designer   = [[Digital Equipment Corporation]]
| bits       = [[64-bit computing|64-bit]]
| introduced = {{Start date and age|1992}}
| design     = [[Reduced instruction set computer|RISC]]
| type       = [[Load–store]]
| encoding   = Fixed
| branching  =
| endianness = [[Endianness#Bi-endianness|Bi]]
| extensions = Byte/Word Extension (BWX), Square-root and Floating-point Convert Extension (FIX), Count Extension (CIX), Motion Video Instructions (MVI)
| open       = Yes<ref name="facts and comments"/>
| gpr        = 31 plus always-zero R31
| fpr        = 31 plus always-0.0 F31
}}
{{Multiple image
| align = right
| direction = vertical
| width = 240
| header = Alpha microprocessors
| image1 = Alpha AXP 21064 diephoto1.jpg
| caption1 = DEC AXP 21064 die photo
| image2 = DEC Alpha 21-35023-13 J40793-28 top.jpg
| caption2 = DEC AXP 21064 package
| image3 = Alpha AXP 21064 card1.jpg
| caption3 = DEC AXP 21064 bare die mounted on business card with some statistics
| image4 = KL Compaq DEC ALPHA 21264C.jpg
| caption4 = Compaq 21264C
}}
'''Alpha''' (original name '''Alpha AXP''') is a [[64-bit computing|64-bit]] [[reduced instruction set computer]] (RISC) [[instruction set architecture]] (ISA) developed by [[Digital Equipment Corporation]] (DEC). Alpha was designed to replace [[32-bit computing|32-bit]] [[VAX]] [[complex instruction set computer]]s (CISC) and to be a highly competitive RISC processor for [[Unix workstation]]s and similar markets.

Alpha was implemented in a series of [[microprocessor]]s originally developed and [[Semiconductor device fabrication|fabricated]] by DEC. These microprocessors were most prominently used in a variety of DEC workstations and servers, which eventually formed the basis for almost all of their mid-to-upper-scale lineup. Several third-party vendors also produced Alpha systems, including [[PC motherboard form factor|PC form factor]] motherboards.

[[Operating system]]s that support Alpha included [[OpenVMS]] (formerly named OpenVMS AXP), [[Tru64 UNIX]] (formerly named DEC OSF/1 AXP and Digital UNIX), [[Windows NT]] (discontinued after [[Windows NT 4.0|NT 4.0]]; and prerelease [[Windows 2000]] [[Software release life cycle|RC2]]),<ref name=alphant>{{cite web 
| author=Aaron Sakovich
| publisher=The AlphaNT Source 
| year=2001 
| url=http://www.alphant.com/articles/windows2000.html
| title=Windows 2000?
| access-date=2007-01-01
| archive-url=https://web.archive.org/web/20080708183609/http://www.alphant.com/articles/windows2000.html
| archive-date=2008-07-08
}}</ref> [[Linux]] ([[Debian]], [[SUSE Linux|SUSE]],<ref name=alphaSUSE>{{cite web
| publisher=SUSE
| year=2000
| url=https://www.suse.com/company/press/2000/11/alpha70.html
| title=SUSE Linux 7.0 Alpha Edition
| access-date=2014-01-08
| archive-date=2014-01-08
| archive-url=https://web.archive.org/web/20140108124236/https://www.suse.com/company/press/2000/11/alpha70.html
| url-status=live
}}</ref> [[Gentoo Linux|Gentoo]] and [[Red Hat Linux|Red Hat]]), [[Berkeley Software Distribution|BSD]] UNIX ([[NetBSD]], [[OpenBSD]] and [[FreeBSD]] up to 6.x), [[Plan 9 from Bell Labs]], and the [[L4 microkernel family|L4Ka::Pistachio]] kernel. A port of [[Ultrix]] to Alpha was carried out during the initial development of the Alpha architecture, but was never released as a product.<ref>{{cite journal|url=http://www.dtjcd.vmsresource.org.uk/pdfs/dtj_v04-04_1992.pdf|title=Using Simulation to Develop and Port Software|author1=George A. Darcy III|author2=Ronald F. Brender|author3=Stephen J. Morris|author4=Michael V. Iles|journal=Digital Technical Journal|volume=4|issue=4|year=1992|pages=181–192}}</ref>

The Alpha architecture was sold, along with most parts of DEC, to [[Compaq]] in 1998.<ref name=Reg.98>{{cite web |website=TheRegister.co.uk |date=November 2, 2016 |url=https://www.theregister.co.uk/2016/11/02/ghost_of_dec_alpha_sees_microsoft_dumb_down_windows_file_compression |title=Ghost of DEC Alpha is why Windows is rubbish at file compression |access-date=September 20, 2018 |archive-date=September 20, 2018 |archive-url=https://web.archive.org/web/20180920122703/https://www.theregister.co.uk/2016/11/02/ghost_of_dec_alpha_sees_microsoft_dumb_down_windows_file_compression |url-status=live}}</ref> Compaq, already an [[Intel]] x86 customer, announced that they would phase out Alpha in favor of the forthcoming [[Hewlett-Packard]]/Intel [[Itanium]] architecture, and sold all Alpha [[intellectual property]] to Intel, in 2001,<ref name="zdnet-compaq">{{cite web|url=https://www.zdnet.com/article/alpha-proved-costly-for-compaq-3002090197/|title=Alpha proved costly for Compaq|last=Popovich|first=Ken|date=2001-06-28|work=[[ZDNet]]|access-date=2016-03-02|archive-date=2016-03-03|archive-url=https://web.archive.org/web/20160303212700/http://www.zdnet.com/article/alpha-proved-costly-for-compaq-3002090197/|url-status=live}}</ref> effectively killing the product. Hewlett-Packard purchased Compaq in 2002, continuing development of the existing product line until 2004, and selling Alpha-based systems, largely to the existing customer base, until April 2007.<ref name=alphasupportend>{{cite web 
 |publisher=HP 
 |url=http://h18002.www1.hp.com/alphaserver/evolution.html 
 |title=Transforming your AlphaServer environment 
 |access-date=2007-01-11 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20070208212316/http://h18002.www1.hp.com/alphaserver/evolution.html 
 |archive-date=2007-02-08 
}}</ref>