Editing Pentagon (computer)

{{Short description|Soviet home computer}}

{{Infobox information appliance
| name = Pentagon
| title = 
| aka = Пентагон
| logo = 
| image = Pentagon-1024SL1.jpg
| caption = Pentagon-1024SL v1.x
| developer = 
| manufacturer = 
| family = 
| type = [[Home computer]]
| generation = 
| releasedate = {{Start date and age|1989}}
| lifespan = 
| price = 
| discontinued = 
| unitssold = 
| unitsshipped = 
| media = tape, floppy disks, hard drives (depending on models)
| os = [[Sinclair BASIC]], [[TR-DOS]]
| power = 
| soc = 
| cpu = КР1858ВМ1/3, Т34ВМ1, Z80A, B, H @ 3.5 MHz (7 MHz turbo mode)
| memory = 48 to 4096[[kilobyte|KB]] (depending on model)
| storage = tape, [[Beta 128 Disk Interface]], [[hard drives]] (depending on models)
| memory card = 
| display = 
| graphics = 256x192, 384x304, 512x192 monochrome
| sound = Beeper, [[Covox]], [[UltraSound]] (depending on model)
| input = 
| controllers = 
| camera = 
| touchpad = 
| connectivity = 
| platform = 
| service = 
| dimensions = 
| weight = 
| topgame = 
| compatibility = [[ZX Spectrum 128]]
| predecessor = 
| successor = 
| related = [[ATM (computer)]]
| website = {{URL|pentagon.nedopc.com}}
}}
The '''Pentagon''' ({{langx|ru|Пентагон}}) [[home computer]] was a clone of the British-made [[Sinclair Research|Sinclair]] [[ZX Spectrum|ZX Spectrum 128]].
It was  manufactured by amateurs in the former [[Soviet Union]], following freely distributable documentation. Its [[Printed circuit board|PCB]] was copied all over the ex-USSR in 1991-1996, which made it a widespread ZX Spectrum clone.
The name "Pentagon" derives from the shape of the original PCB (Pentagon 48), with a diagonal cut in one of the corners.
<ref name="auto">{{Cite web|url=http://speccy.info/Pentagon|title=Pentagon — SpeccyWiki|website=speccy.info}}</ref>

Many simple devices (upgrades) were invented to connect to the Pentagon with some soldering.<ref>{{Cite web|url=http://www.worldofspectrum.org/rusfaq/|title=Russian Most Popular Spectrum Models|website=www.worldofspectrum.org|access-date=2004-09-08|archive-date=2012-07-16|archive-url=https://web.archive.org/web/20120716193838/http://www.worldofspectrum.org/rusfaq/|url-status=dead}}</ref>

==Versions==
*'''Pentagon 48K''' (1989 by Vladimir Drozdov)
*'''Pentagon 128K''' (1991)
*'''Pentagon 128K 2+''' (1991 by ATM)
*'''Pentagon 128K 3+''' (1993 by Solon)
*'''Pentagon 1024SL v1.x''' (2005 by Alex Zhabin)
*'''Pentagon-1024SL v2.x''' (2006 by Alex Zhabin)
*'''Pentagon ver.2.666''' (2009 by Alex Zhabin)<ref>{{Cite web|url=http://pentagon.nedopc.com/info.htm|title=Информация|website=pentagon.nedopc.com}}</ref>

The Pentagon 1024SL v2.3 included most of the upgrades of the standard Spectrum architecture, including 1024&nbsp;[[kilobyte|KB]] [[random access memory|RAM]], [[Beta 128 Disk Interface]] and ZX-BUS slots (especially for [[Integrated Drive Electronics|IDE]] and General Sound cards). This model also featured a "turbo" mode (7 MHz instead of the original's 3.50&nbsp;MHz).<ref name="auto2">{{Cite web |title=Pentagon — SpeccyWiki |url=http://speccy.info/Pentagon |website=speccy.info}}</ref>

[[Image:p1024sl2 motherboard.jpg|thumb|200px|Pentagon-1024SL v2.x]]

===Upgrades from the original ZX Spectrum===
* Extra RAM ranging from 256 KB to 4 MB
* Several [[sound card]] possibilities such as [[Covox]] (usually named as ''SounDrive'') or [[Direct memory access|DMA]] [[UltraSound]]
* Additional video modes: 512x192 monochrome,  384x304, 256x192x15 (with no [[Attribute clash]])
* [[CMOS]] with persistent [[real-time clock]]
* [[IDE Controller]] for [[hard drives]]
* "[[Turbo Mode]]" that clocks the CPU up to 7 MHz

==References==
{{reflist}}

== External links ==
{{commonscat|Pentagon computers}}
*[http://www.worldofspectrum.org/rusfaq/ Russian most popular Spectrum models] {{Webarchive|url=https://web.archive.org/web/20120716193838/http://www.worldofspectrum.org/rusfaq/ |date=2012-07-16 }}
*[http://pentagon.nedopc.com/ Pentagon 1024 official site] {{in lang|ru}}
*[http://speccy.info/w/images/5/58/Pentagon_48K_Beta_Disk_Schematics.djvu Schematic diagram of the Pentagon 48K and drive controller (DjVu)]
*[http://speccy.info/w/images/8/84/Pentagon_128K_Schematic.djvu 128K Schematic diagram of the Pentagon (the DjVu)]
*[http://speccy.info/w/images/8/88/Pentagon_128K_1991_Schematic.png Schematic and wiring diagrams Pentagon 128K 1991, revised and enlarged version (PNG)]
*[http://speccy.info/w/images/1/1e/Pentagon_128K_Board_Layout.png Wiring diagram 128K the Pentagon (the PNG)]
*[https://www.facebook.com/groups/2010022152575001/ NEW English FaceBook Group]
{{Sinclair computers and clones}}

{{List of Soviet computer systems}}

{{DEFAULTSORT:Pentagon (Computer)}}
[[Category:ZX Spectrum clones]]
[[Category:Computer-related introductions in 1989]]
[[Category:1989 establishments in the Soviet Union]]
[[Category:Soviet computer systems]]