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Beta Disk Interface is a disk interface for ZX Spectrum computers. It was developed by Technology Research Ltd (United Kingdom), in 1984〔Sinclair User March 84, p. 34〕 and released in 1985 with price £109.25 (or £249.75 with one disk drive).〔Sinclair User Jan 85, p. 73〕 Beta 128 Disk Interface is a 1987〔Sinclair User Jan 87〕 version supporting ZX Spectrum 128 machines (difference is in access points addresses). Beta disk interfaces were distributed with TR-DOS operating system in ROM, also attributed to Technology Research Ltd. Latest firmware version is 5.03 (1986). The interface was based on the WD1793 chip.〔http://k1.dyndns.org/Vintage/Sinclair/82/Peripherials/Disc%20Interfaces/Beta%20128%20Disc%20Interface,%20TRDOS%20%28Technology%20Research%29/TRDOS/TR-DOS%20Programming.txt〕 The interface handles single and double sided, 40 and 80 track double density floppy disks, up to 4 drives. ==Clones== This interface was popular for its simplicity, and Beta 128 Disk Interface was cloned all around USSR. First known USSR clones were ones produced by НПВО "Вариант" (Leningrad) in 1989.〔Sinclair ZX Spectrum. Beta Disc / TR-DOS. Аппаратные средства. Стандартный интерфейс дисковода. - С.-Петербург, 1994〕 Beta 128 schematics are included in various Russian ZX Spectrum clones. Some variants of schematics support only 2 drives. Phase correction of drive data signal is made different ways.〔Рюмик С. Контроллер дисководов. Канал записи / Радиолюбитель. Ваш компьютер, 1998, NN10-12; 1999, N1〕〔Рюмик С. Контроллер дисководов. Канал чтения / Радиолюбитель. Ваш компьютер, 1999, N4-8〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Beta Disk Interface」の詳細全文を読む スポンサード リンク
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