View source for Beta Disk Interface

{{Short description|Disk interface for ZX Spectrum computers}}
[[File:Beta-Disk Interface card.jpg|thumb|Soviet clone of Beta Disk Interface]]

'''Beta Disk Interface''' is a disk interface for [[ZX Spectrum]] computers, developed by Technology Research Ltd. ([[United Kingdom]]) in 1984<ref>{{Cite news |date=March 1984 |title=Disk interface takes waiting out of wanting |url=https://worldofspectrum.org/archive/magazines/sinclair-user/24/0/1984/3/0#34 |work=Sinclair User |pages=34}}</ref> and released in 1985, with a price of £109.25 (or £249.75 with one disk drive).<ref>{{Cite news |date=January 1985 |title=More memory less labour |url=https://worldofspectrum.org/archive/magazines/pages/sinclair-user/34/73 |work=Sinclair User |pages=73}}</ref> 

'''Beta 128 Disk Interface''' is a 1987<ref>{{Cite web |title=Beta 128 Disk Interface |url=https://spectrumcomputing.co.uk/entry/1000033 |access-date=2025-02-02 |website=Spectrum Computing - ZX Spectrum games, software and hardware}}</ref> version, supporting [[ZX Spectrum 128]] machines (due to different access point addresses).

Beta Disk Interfaces were distributed with the [[TR-DOS]] operating system in ROM, also attributed to ''Technology Research Ltd.''. The interface was based on the [[WD1771|WD1793]] chip.<ref>{{cite web |last=Extreme |first=Mac Buster |date=1999 |title=Tr-Dos v5.xx - programmer's manual |url=http://k1.dyndns.org/Vintage/Sinclair/82/Peripherials/Disc%20Interfaces/Beta%20128%20Disc%20Interface,%20TRDOS%20%28Technology%20Research%29/TRDOS/TR-DOS%20Programming.txt |url-status=dead |archiveurl=https://web.archive.org/web/20140409113112/http://k1.dyndns.org/Vintage/Sinclair/82/Peripherials/Disc%20Interfaces/Beta%20128%20Disc%20Interface%2C%20TRDOS%20%28Technology%20Research%29/TRDOS/TR-DOS%20Programming.txt |archivedate=2014-04-09 |accessdate=2013-12-16}}</ref> Latest [[firmware]] version is 5.03 (1986).

The Beta Disk Interface handles single- and double-sided, 40- or 80-track double-density [[floppy disk]]s, and up to four drives.

==Clones==
This interface was popular for its simplicity, and the Beta 128 Disk Interface was [[Clone (computing)|cloned]] all around the [[USSR]]. The first known USSR clones were ones produced by НПВО "Вариант" (''NPVO "Variant"'', [[Leningrad]]) in 1989.<ref>Sinclair ZX Spectrum. Beta Disc<!--sic!--> / TR-DOS. Аппаратные средства. Стандартный интерфейс дисковода. - С.-Петербург, 1994</ref> 

Beta 128 schematics are included in various [[List of ZX Spectrum clones#Soviet/Russian|Soviet/Russian ZX Spectrum clones]], but some variants only support two drives. Phase correction of the drive data signal is also implemented differently.<ref>Рюмик С. Контроллер дисководов. Канал записи / Радиолюбитель. Ваш компьютер, 1998, NN10-12; 1999, N1</ref><ref>Рюмик С. Контроллер дисководов. Канал чтения / Радиолюбитель. Ваш компьютер, 1999, N4-8</ref>

[[File:Beta Disk 128C.jpg|thumb|Czech clone Beta Disk 128C]]
Between 2018 and 2021, Beta Disk clones were produced in the [[Czech Republic]], with the names such as Beta Disk 128C, 128X and 128 mini.{{fact|date=December 2022}}

==Operating systems support==
[[File:Beta Disk 128C (electronics).jpg|thumb|Beta Disk 128C (electronics)]]

* [[TR-DOS]]
* [[iS-DOS]]
* [[CP/M]] (various hack versions)
* [[DNA OS]]

==See also==
* [[DISCiPLE]]
[[File:Bdi128mini 01.jpg|thumb|Set of controller and floppy box from 2021]]
[[File:Bdi128mini 02.jpg|thumb|Controller Beta Disk 128 mini from 2021]]

==References==
<references />

==External links==
{{commonscat|Beta Disk Interface}}
* [http://trd.speccy.cz/ Virtual TR-DOS]
{{Sinclair computers and clones}}
[[Category:ZX Spectrum]]
[[Category:Computer storage devices]]