Elektronika BK

Infobox computer
Photo =
Type = Home computer
Released = 1985
Discontinued =
Processor = K1801VM1 @3MHz (BK-0010), @4.6MHz (BK-0011), @4MHz (BK-0011M)
OS = Vilnius BASIC (ROM embedded), OS BK-11, various hobby OSes
Memory = 32KiB

Elektronika BK is a series of Soviet home computers trademarked as Elektronika that share architectural similarities with PDP-11. They are based on the К1801ВМ1 (Soviet LSI-11-compatible CPU) and were available in several different versions.

"BK" ("БК") is abbreviation _ru. Бытовой Компьютер - domestic (or home) computer.

All models had one free Q-Bus slot and a parallel port used to connect peripherals such as printer and mouse.

Models

Elektronika BK-0010 (Электроника БК-0010) was the first model (released in January 1985). It had a membrane keyboard, 32 KiB RAM (half of which was used for video memory), 32 KiB ROM with FOCAL interpreter, 3 MHz 16 bit CPU, a TV connected via EuroConnector (a version of SCART) or a monitor could be used as a display device. A tape recorder was used for data storage in factory configuration.

There also was a separate Euroconnector for a color TV. It would display 256×256 graphics in four colours or 512×256 in monochrome mode.

Although the instruction set and the I/O ports were described in the documentation provided with the computer, the assembly language development tools were not included. A gray market of games and development software flourished.

Disk drive controllers became available from third-party vendors.

Elektronika BK-0010-01 was more powerful with a conventional keyboard and a BASIC dialect p-code compiler (Vilnius BASIC). FOCAL interpreter was shipped in an external ROM card which could be inserted into the Q-Bus slot.

Elektronika BK-0010Sh (Электроника БК-0010Ш) was a model intended specially for school use. It had a special network adapter which could be inserted into the Q-Bus slot.

Elektronika BK-0011 came in 1990, had 128 kiB of RAM divided into 16 KiB pages, 4 MHz CPU, a newer version of BASIC in ROM, 16 video palettes, and had the possibility to use a disk drive (The disk drive adaptor could also be used with BK-0010 series). One of the operating system was ANDOS, although officially computer was shipped with OS BK-11, a modification of RT-11.

Elektronika BK-0011M was a modified version of Elektronika BK-0011, which fixed some incompatibilities with BK-0010. In particular, the sound in programs for BK-0010 didn't work on BK-0011. It was fixed in BK-0011M. BK-0011M quickly went into production, and most of BK-0011 series computers were actually BK-0011M.

A 16-bit universal port with separate input and output busses, present in all models, allowed to utilize a multitude of peripheral devices (joystick, mouse, printers, various sound output devices, etc.) for home entertainment, education, and for data acquisition and monitoring in various industrial and research settings.

Enthusiasts managed to connect more advanced devices to BK series computers. They developed a hard disk controller, and 2.5" HDDs were successfully used with BK computer. Other popular enhancement was an AY-3-8912 sound chip.

Mods

It was not uncommon among users to install one or two mechanical switches that made using the computer more convenient. Some of the common mods were:

* Reset button. Programs often hung; also, some games did not have a properly implemented Exit function. Without the button, the computer had to be reset by power cycling, eventually leading to a worn out power switch on the external power supply.

* Pause switch. The switch activated hardware suspension of instructions execution in the processor. The pause switch was useful for pausing games, most of which did not have a pause key. A few games, however, did not behave gracefully after being returned from the suspension, because the programmable hardware timer built into the processor chip was still running while the instructions execution was suspended.

* Clock speed switch (“turbo” switch). Changed the processor clock speed from the standard 3 MHz (BK-0010* series) to 4 or 6 MHz, or from the standard 4 MHz (BK-0011* series) to 3 or 6 MHz. Not all processor samples worked reliably at 6 MHz; the possibility of such overclocking had to be determined experimentally for each sample. Switching the clock speed changed the pace of dynamic games. The turbo switch usually had to be installed together with the pause switch, because the simplest circuit for switching the clock speed produced bad shapes in the clock signal due to contact bounce when the mechanical switch was flipped, running the risk of hanging the software execution unless the processor was in the suspended state.

* “Sound on/off” switch, or sound volume knob which adjusted the volume level of the internal piezoelectric speaker using a potentiometer. While the modder was at it, the speaker could be replaced by a louder one.

These modifications were relatively simple and could be carried out by users who knew how to handle a soldering iron. Most of the people in the cottage industry of selling programs could also do the mods for a small fee.

Emulators

There are various software emulators of BK for modern IBM PC-compatible computers. An emulator is able to run at a much higher speed than the original BK.

References

External links

* [http://rk86.com/frolov/bk0011.htm Elektronika BK 0011] in the Soviet Calculator Collection
* [http://iiorao.ru/iio/pages/history/history_COMP/comp1/ Электроника БК 0010 на сайте Института информатизации]
* [http://old.h1.ru/xussr/0010.shtml Computer Museum article about Elektronika BK-0010/11]
* [http://demoscene.ru/info/article.php3?02013/ The Outsider's Story: an article in Computerra Magazine (full version)]
* [http://bk0010.narod.ru/ BК-0010 memories, software, documentation]
* [http://www.users.itl.net.ua/~prool/BK-0010.html BK-0010 page by Sergey Pustovoytov]
* [http://vanyas.chat.ru/world_bk/ another BK-0010/11M page]
* [http://www.mailcom.com/bk0010/ BК-0010 Nostalgia Page]
* [http://bk.default.ru/ An Elektronika BK emulator by Sergey Kamnev]
* [http://pouet.net/prodlist.php?platform%5B%5D=BK-0010%2F11M&order=&x=35&y=10&page=1&order=/ Demos and intros for BK-0010/11]
* [http://groups.google.com/group/bk0010 БК-0010 — советский персональный компьютер] — a Google Groups group, English is ok
* [http://www.oldbits.de/collection/elektronika_bk0010.jpgimage] of the original flat-keyboard model from [http://www.oldbits.de oldbits.de]
* [http://www.zolitude.lv/museum/data/exhibits_data/5.htm Latvian page about BK]