Editing DEC Alpha (section)

==Implementations==
At the time of its announcement, Alpha was heralded as an architecture for the next 25 years. While this was not to be, Alpha has nevertheless had a reasonably long life. The first version, the ''[[Alpha 21064]]'' (otherwise named the ''EV4'') was introduced in November 1992 running at up to 192&nbsp;MHz; a slight shrink of the die (the ''EV4S'', shrunk from 0.75&nbsp;μm to 0.675&nbsp;μm) ran at 200&nbsp;MHz a few months later. The 64-bit processor was a [[superpipelined]] and [[superscalar]] design, like other RISC designs, but nevertheless outperformed them all and DEC touted it as the world's fastest processor. Careful attention to circuit design, a hallmark of the Hudson design team, like a huge centralized clock circuitry, allowed them to run the CPU at higher speeds, even though the microarchitecture was fairly similar to other RISC chips. In comparison, the less expensive [[Original Intel Pentium (P5 microarchitecture)|Intel Pentium]] ran at 66&nbsp;MHz when it was launched the following spring.

The ''[[Alpha 21164]]'' or ''EV5'' became available in 1995 at processor frequencies of up to 333&nbsp;MHz. In July 1996 the line was speed bumped to 500&nbsp;MHz, in March 1998 to 666&nbsp;MHz. Also in 1998 the ''[[Alpha 21264]]'' (''EV6'') was released at 450&nbsp;MHz, eventually reaching (in 2001 with the ''21264C''/''EV68CB'') 1.25&nbsp;GHz. In 2003, the ''[[Alpha 21364]]'' or ''EV7'' ''Marvel'' was launched, essentially an EV68 core with four 1.6 GB/s{{efn|In the context of data transfer, 1 GB is used to mean 1 billion bytes}} inter-processor communication links for improved [[multiprocessor]] system performance, running at 1 or 1.15&nbsp;GHz.

In 1996, the production of Alpha chips was licensed to [[Samsung Electronics|Samsung Electronics Company]]. Following the purchase of Digital by [[Compaq]] the majority of the Alpha products were placed with [[API NetWorks]], Inc. (formerly Alpha Processor Inc.), a private company funded by Samsung and Compaq. In October 2001, [[Microway]] became the exclusive sales and service provider of API NetWorks' Alpha-based product line.

On June 25, 2001, Compaq announced that Alpha would be phased out by 2004 in favor of [[Intel]]'s [[Itanium]], canceled the planned ''[[Alpha 21464|EV8]]'' chip, and sold all Alpha intellectual property to [[Intel]].<ref name="zdnet-compaq"/> [[Hewlett-Packard]] merged with Compaq in 2002; HP announced that development of the Alpha series would continue for a few more years, including the release of a 1.3&nbsp;GHz EV7 variant named the ''EV7z''. This would be the final iteration of Alpha, the 0.13&nbsp;μm ''EV79'' also being canceled.

Alpha is also implemented in the ''Piranha'', a research prototype developed by Compaq's Corporate Research and Nonstop Hardware Development groups at the Western Research Laboratory and Systems Research Center. ''Piranha'' is a [[Multi-core processor|multicore]] design for [[transaction processing]] workloads that contains eight simple cores. It was described at the 27th Annual International Symposium on Computer Architecture in June 2000.<ref>{{cite conference|author1=Luiz André Barroso |author2=Kourosh Gharachorloo |author3=Robert McNamara |author4=Andreas Nowatzyk |author5=Shaz Qadeer |author6=Barton Sano |author7=Scott Smith |author8=Robert Stets |author9=Ben Verghese|year=2000|title=Piranha: A Scalable Architecture Based on Single-Chip Multiprocessing|doi=10.1145/339647.339696|conference=27th Annual International Symposium on Computer Architecture|doi-access=free }}</ref>

Early revisions of the [[Sunway (processor)|Sunway]] architecture are claimed to be based on Alpha, however since the [[SW26010]], Sunway uses a new instruction set architecture unrelated to Alpha.<ref>{{cite web|url=http://laotsao.wordpress.com/2011/10/29/sw1600-and-alpha-21164/ |title=SW1600 and Alpha 21164|access-date=2011-10-29 |author=Hung-Sheng Tsao |date=2011-10-29 |work=LaoTsao's Weblog}}</ref><ref name=dongarra2016>{{Cite web|url=http://www.netlib.org/utk/people/JackDongarra/PAPERS/sunway-report-2016.pdf|title=Report on the Sunway TaihuLight System|last=Dongarra|first=Jack|date=2016-06-20|website=www.netlib.org|access-date=2016-06-20}}</ref>

===Model history===
{| class="wikitable sortable" style="font-size:97%; text-align:center;"
! Model
! Model number
! Year
! Frequency [MHz]
! Process [μm]
! Transistors [millions]
! Die size [mm<sup>2</sup>]
! IO pins
! Power [W]
! Voltage
! Dcache [KB]<ref group=lower-alpha>In the context of cache memory, 1 KB = 1024 [[byte]]s; 1 MB = 1024 KB</ref>
! Icache [KB]
! Scache
! Bcache
! [[#ISA|ISA]]
|-
!EV4
|[[Alpha 21064|21064]]||1992||100&ndash;200||0.75||1.68||234||290||30||3.3||8||8||–||128&nbsp;KB&ndash;16&nbsp;MB||&nbsp;
|-
!EV4S
|21064||1993||100&ndash;200||0.675||1.68||186||290||27||3.3||8||8||–||128&nbsp;KB&ndash;16&nbsp;MB||&nbsp;
|-
!EV45
|21064A||1994||200&ndash;300||0.5||2.85||164||||33||3.3||16||16||–||256&nbsp;KB&ndash;16&nbsp;MB||&nbsp;
|-
!LCA4
|21066||1993||100&ndash;166||0.675||1.75||209||||21||3.3||8||8||–||&nbsp;||&nbsp;
|-
!LCA4
|21068||1994||66||0.675||1.75||209||||9||3.3||8||8||–||&nbsp;||&nbsp;
|-
!LCA45
|21066A||1994||100&ndash;266||0.5||1.8||161||||23||3.3||8||8||–||&nbsp;||&nbsp;
|-
!LCA45
|21068A||1994||100||0.5||1.8||161||||||3.3||8||8||–||&nbsp;||&nbsp;
|-
!EV5
|[[Alpha 21164|21164]]||1995||266&ndash;500||0.5||9.3||299||296||56||3.3/2.5||8||8||96&nbsp;KB||Up to 64&nbsp;MB||R
|-
!EV56
|21164A||1996||366&ndash;666<ref name="facts and comments"/>||0.35||9.66<ref name="facts and comments"/>||209||||31&ndash;55<ref name="facts and comments"/>||3.3/2.5<ref name="facts and comments"/>||8||8||96&nbsp;KB||Up to 64&nbsp;MB||R,B
|-
!PCA56
|21164PC||1997||400&ndash;533||0.35||3.5||141||264||26&ndash;35||3.3/2.5||8||16||–||512&nbsp;KB&ndash;4&nbsp;MB||R,B,M
|-
!PCA57
|21164PC||&nbsp;||600&ndash;666||0.28||5.7||101||283||18&ndash;23||2.5/2.0||16||32<ref name="facts and comments">{{cite web
 |url = http://www.alasir.com/articles/alpha_history/
 |title = Alpha: The History in Facts and Comments
 |access-date = Nov 22, 2008
 |author = Paul V. Bolotoff
 |date = 21 April 2007
 |archive-url = https://web.archive.org/web/20131203130550/http://alasir.com/articles/alpha_history/
 |archive-date = 3 December 2013
 |url-status = dead
}}</ref>
||–||512&nbsp;KB&ndash;4&nbsp;MB||R,B,M
|-
!EV6
|[[Alpha 21264|21264]]||1998||450&ndash;600||0.35||15.2||314||389||73||2.0||64||64||–||2&ndash;8&nbsp;MB||R,B,M,F
|-
!EV67
|21264A||1999||600&ndash;750||0.25||15.2||210||389||&nbsp;||2.0||64||64||–||2&ndash;8&nbsp;MB||R,B,M,F,C
|-
!EV68AL
|21264B||2001||800&ndash;833||0.18||15.2||125||&nbsp;||&nbsp;||1.7||64||64||–||2&ndash;8&nbsp;MB||R,B,M,F,C,T
|-
!EV68CB
|21264C||2001||1000&ndash;1250||0.18||15.2||125||&nbsp;||65&ndash;75||1.65||64||64||–||2&ndash;8&nbsp;MB||R,B,M,F,C,T
|-
!EV68CX
|21264D||&nbsp;||&nbsp;||&nbsp;||&nbsp;||&nbsp;||&nbsp;||&nbsp;||1.65||64||64||–||2&ndash;8&nbsp;MB||R,B,M,F,C,T
|-
!EV7
|[[Alpha 21364|21364]]||2003||1000&ndash;1150||0.18||130||397||||125||1.5||64||64||1.75&nbsp;MB||–||R,B,M,F,C,T
|-
!EV7z
|21364||2004||1300||0.18||130||397||||125||1.5||64||64||1.75&nbsp;MB||–||R,B,M,F,C,T
|-
!colspan=16| Cancelled
|-
!EV78/EV79
|21364A||Slated for 2004||1700||0.13||152||300||||120||1.2||64||64||1.75&nbsp;MB||–||R,B,M,F,C,T
|-
!EV8
|[[Alpha 21464|21464]]||Slated for 2003||1200&ndash;2000||0.125||250||420||1800||??||1.2||64||64||3&nbsp;MB||–||R,B,M,F,C,T
|}

;ISA extensions:

* '''R''' – Hardware support for rounding to infinity and negative infinity.<ref>{{cite web
| url = http://www.mostang.com/~davidm/papers/expo97/paper/doc003.html
| title = Overview of Alpha Family
| access-date = Dec 9, 2009
| author = David Mosberger
| archive-date = January 20, 2009
| archive-url = https://web.archive.org/web/20090120232139/http://mostang.com/~davidm/papers/expo97/paper/doc003.html
| url-status = live
}}</ref>
* '''B''' – BWX, the "Byte/Word Extension", adding instructions to allow 8- and 16-bit operations from memory and I/O
* '''M''' – MVI, "multimedia" instructions
* '''F''' – FIX, instructions to move data between integer and floating-point registers and for square root
* '''C''' – CIX, instructions for counting and finding bits
* '''T''' – support for prefetch with modify intent to improve the performance of the first attempt to acquire a lock