View source for Galaksija (computer)

{{Use dmy dates|date=June 2014}}
{{Infobox information appliance
| name = {{lang|sr|Galaksija}}
| image = Galaksija 1984.jpg
| caption = Main board of Galaksija during assembly process
| manufacturer = 
| type = [[Home computer]]
| releasedate = {{Start date and age|1983}}
| price = <!-- this is price at initial release, not the current price -->
| connectivity = 
| lifespan = 
| unitssold = 
| media = [[Compact Cassette (data)|Compact Cassette]]s
| os = [[Galaksija BASIC]]
| input = [[keyboard (computing)|Keyboard]]
| camera = 
| power = 
| cpu = [[Zilog Z80]]A
| CPUspeed = 3.072 MHz
| storage = 
| memory = 2–6KB [[RAM]], 4–8KB [[read-only memory|ROM]]
| display = 64x48 monochrome
| audio = 
| service = <!-- online service/s offered -->
| dimensions = 
| weight = 
| touchpad = 
| predecessor = 
| successor = [[Galaksija Plus]]
| related = 
}}
The '''Galaksija''' ({{lang-sr-Cyrl|Галаксија}}; {{IPA|sr|galǎksija}}, meaning "[[Galaxy]]") was a build-it-yourself computer designed by [[Voja Antonić]]. It was featured in the special edition ''Računari u vašoj kući'' (''Computers in your home'', written by [[Dejan Ristanović]]) of a popular eponymous science magazine, published late December 1983 in [[Belgrade]], [[SFRY|Yugoslavia]]. Kits were available but not required as it could be built entirely out of standard off-the-shelf parts. It was later also available in complete form.

== History ==
In the early eighties, restrictions in [[Socialist Federal Republic of Yugoslavia|SFR Yugoslavia]] prevented importing computers into the country.<ref name="Eby">{{cite web |last1=Eby |first1=Michael |title=The Lost History of Socialism's DIY Computer |url=https://www.jacobinmag.com/2020/08/computer-yugoslavia-galaksija-voja-antonic |publisher=[[Jacobin (magazine)|Jacobin]] |date=8 February 2020}}</ref> At the same time, even the cheapest computers available in the West were nearing average monthly salaries.<ref name="Eby" /> This meant that only a relative minority of people owned one — mostly a [[ZX Spectrum]] or a [[Commodore 64]], though most Yugoslavs were only familiar with a programmable calculator.<ref name="eurogamer">{{cite web |last1=Packwood |first1=Lewis |title=The story of Yugoslavia's DIY computer revolution |url=https://www.eurogamer.net/articles/2013-07-30-the-story-of-yugoslavias-diy-computer-revolution |website=Eurogamer |date=30 July 2013}}</ref>

According to his own words, some time in 1983, [[Voja Antonić]], while vacationing in Hotel Teuta in [[Risan]], was reading the application handbook for the RCA [[RCA 1802|CDP1802]] [[central processing unit|CPU]] and stumbled upon CPU-assisted video generation.<ref name="1983Galaksija">{{cite web |last=Antonić |first=Voja |authorlink=Voja Antonić |title=1983: Galaksija |url=http://www.paralax.rs/pr83.htm |url-status=dead |archive-url=https://web.archive.org/web/20090504112705/http://www.paralax.rs/pr83.htm |archive-date=4 May 2009 |access-date=2010-06-17 |df=dmy-all}}</ref><ref>{{Cite news |last=Packwood |first=Lewis |date=2024-10-24 |title=How one engineer beat the ban on home computers in socialist Yugoslavia |url=https://www.theguardian.com/games/2024/oct/24/how-one-engineer-beat-the-ban-on-home-computers-in-socialist-yugoslavia |access-date=2024-10-25 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref> Since the CDP1802 was very primitive, he decided that a [[Zilog Z80]] processor could perform the task as well.

Before he returned home to [[Belgrade]], he already had the conceptual diagrams of a computer that used software to generate a video picture.<ref name="eurogamer" /> Although using software as opposed to hardware would significantly reduce his design's performance, it also simplified the hardware and reduced its cost.<ref name="Alberts & Odenziel">{{cite book |last1=Alberts |first1=Gerard |last2=Oldenziel |first2=Ruth |author2-link=Ruth Oldenziel|title=Hacking Europe: From Computer Cultures to Demoscenes |date=2014 |publisher=Springer |isbn=978-1-44715-493-8 |pages=119–121 |url=https://books.google.com/books?id=z8RsBAAAQBAJ&pg=PA119}}</ref>

His next step was to find a magazine to publish the diagrams in. The obvious choice was [[SAM Magazine]] published in [[Zagreb]], but due to prior bad experiences he decided to publish elsewhere.<ref name="1983Galaksija"/> Near the same time that Antonić made his discovery, Dejan Ristanović, a computer programmer and journalist was entrusted with preparing a special edition of the ''Galaksija'' magazine that would be focused on home computers.<ref name="Eby" /> After Ristanović and Antonić met, they decided to collaborate and publish the computer's diagram in a special issue of the magazine entitled ''Računari u vašoj kući'' (''Computers in your home'').<ref name="Eby" /> It was released late December 1983.<ref name="eurogamer" /> The name of the magazine (''Galaksija'') would become twinned with the name of the computer.<ref name="eurogamer" />

Antonić and Ristanović guesstimated that around a thousand people would try to build the computer by themselves, given that the magazine's circulation was 30,000.<ref name="Alberts & Odenziel" /> Some 8,000 people wound up ordering the build-it-yourself kits from Antonić.<ref name="Alberts & Odenziel" /> This number may in reality be greater if people who did not purchase any kits (including [[printed circuit board|PCB]] and [[read-only memory|ROMs]]) were accounted for.

Components were provided by various manufacturers and suppliers:<ref name="Laphroaig">{{cite book |last1=Laphroaig |first1=Manul |title=PoC or GTFO, Volume 2 |date=2018 |publisher=No Starch Press |isbn=978-1-59327-935-6 |pages=98–100 |url=https://books.google.com/books?id=QsFQDwAAQBAJ&pg=PT98}}</ref>
* MIPRO and [[Elektronika Buje|Elektronika]] from [[Buje]], together with the Institute for Electronics and Vacuum Technology (Serbian: ''Institut za elektroniku i vakuumsku tehniku'') delivered PCBs, [[computer keyboard|keyboards]] and masks
* [[Mikrotehnika]] from [[Graz]] sent [[integrated circuit]]s
* [[Voja Antonić]] personally programmed all [[EPROM]]s
* [[Galaksija (magazine)|Galaksija]] collected requisition forms and organized deliveries

Later, the Institute for School Books and Teaching Aids (Serbian: ''Zavod za udžbenike i nastavna sredstva''), together with [[Elektronika Inženjering]], started mass commercial production of Galaksija computers, mainly to be delivered to schools.<ref name="ristovic">{{cite web |last1=Ristanović |first1=Dejan |author1-link=Dejan Ristanović |title=Priča o Galaksiji |trans-title=The story of the Galaksija |url=https://www.dejanristanovic.com/galaks.htm |website=Dejan Ristanovic}}</ref>

== Technical specifications ==
* [[central processing unit|CPU]]: [[Zilog]] [[Zilog Z80|Z80A]] 3.072 [[MHz]]
* [[Galaksija (computer)#ROM "A"|ROM "A" or "1"]] – 4 KB (2732 [[EPROM]]) contains bootstrap, core control and [[Galaksija BASIC]] interpreter code
* [[Galaksija (computer)#ROM "B"|ROM "B" or "2"]] – 4 KB (''optional'', also 2732 EPROM) – additional Galaksija BASIC commands, [[assembly language#Assembler|assembler]], [[machine code monitor]], etc.
* [[Galaksija (computer)#Character ROM|Character ROM]] – 2 KB (2716 EPROM) contains character definitions, characters are 8×13 pixels, the block graphics were vertically divided in a 4:5:4 scheme, and horizontally in a 4:4 scheme.
* [[random access memory|RAM]]: 2 to 6 KB of 6116 [[static RAM]] in base model, expandable to 54 [[kilobyte|KB]]
* [[Text mode]] 32 x 16 characters, [[monochrome]]
* [[Pseudographics]]: 2×3 [[dot matrix]] combinations in graphic character subset – 64 distinct patterns in total
* Sound: None according to specifications, but tape interface was occasionally used as audio output port – like the "EAR" port on [[ZX Spectrum]] can be used both as audio and [[cassette tape interface]]. See [[#"Cassette" port|cassette port]] for details.
* [[Storage media]]: [[cassette tape]], recording at 280 [[bit rate|bit/s]] rate
* I/O ports: 44-pin [[edge connector]] with [[Z80]] Bus, tape ([[DIN connector]]), monochrome video out ([[PAL]] timings, [[DIN connector]]), and [[ultra high frequency|UHF]] TV out ([[RCA connector]])

== BASIC ROMs ==
[[Galaksija BASIC]] is a [[BASIC]] [[interpreter (computing)|interpreter]] originally partly based on code taken from [[TRS-80]] Level 1 BASIC, which the creator believed to have been a [[Microsoft BASIC]].<ref name="1983Galaksija"/> However, after extensive modifications to include video generation code (as the [[CPU]] was a major participant to reduce the cost of hardware) and improve the [[programming language]], what remained from the original is said to be mainly [[control flow|flow-control]] and [[floating point]] code. It was fully contained in 4 [[kilobyte|KB]] [[Galaksija (computer)#ROM "A"|ROM "A" or "1"]]. Additional [[Galaksija (computer)#ROM "B"|ROM "B" or "2"]] provided more Galaksija BASIC commands, assembler, monitor, etc.

=== ROM "A" ===
The chip labeled as "A" by the creator of Galaksija, [[Voja Antonić]] was commonly referred to as "ROM 1" or just "ROM". ROM "A" contained [[booting|bootstrap]] code of Galaksija, its control code (rudimentary [[operating system]]), video generation code (as Galaksija did not have advanced video subsystem its [[Z80]] [[CPU]] was responsible even for generating [[video signal]]) and [[Galaksija BASIC]].

Fitting all this functionality in 4 KB of 2732 [[EPROM]] required a lot of effort and some sacrifices. For example, some message text areas were also used actual code (e.g. "READY" message) and the number of error messages was reduced to only three ("WHAT?", "HOW?" and "SORRY").<ref name="eurogamer" />

=== ROM "B" ===
[[read-only memory|ROM]] "B" of the Galaksija is a 2732 [[EPROM]] [[integrated circuit|chip]] that contains extensions to the original [[Galaksija BASIC]] available in [[Galaksija (computer)#ROM "A"|base ROM ("A")]]. It was labeled as "B" by the creator of the Galaksija, [[Voja Antonić]], but was commonly referred to as "ROM 2".

ROM "B" contained added Galaksija BASIC commands and functions (mostly [[trigonometry|trigonometric]]) as well as a [[Z80]] [[assembly language#Assembler|assembler]] and a [[machine code monitor]]. This ROM was not required and was an optional upgrade. Although planned on the mainboard, the content of ROM "B" was not automatically initialized during [[booting]]. Instead, users had to execute a Galaksija BASIC command to run a [[machine code]] program from ROM "B" before they can gain additional features. This also meant that even Galaksijas with ROM "B" plugged in can behave entirely as base models.

== Character ROM ==
[[File:Galaksija charset.png|thumb|The full character set, featuring the logo of Elektronika Inženjering]]
Character [[read-only memory|ROM]] of [[home computer]] Galaksija is a 2716 [[EPROM]] [[integrated circuit|chip]] that contains graphical definitions of Galaksija's character set. It had no special name and was labeled "2716" after the type of 2 KB EPROM needed.

The character encoding is based on [[ASCII]], but has several modifications:
* There are no lowercase characters (like ASCII-1963)<ref name="manual"/><ref name="Tablix">{{cite web |last1=Šolc |first1=Tomaž |title=Avian's Blog: Testing Galaksija's memory |url=https://www.tablix.org/~avian/blog/archives/2017/09/testing_galaksijas_memory/ |website=Avian's Blog |publisher=Tablix |access-date=15 November 2023 |date=26 September 2017}}</ref>
* Codepoints 91 to 94 (0x5B to 0x5E) represent the [[Serbian language|Serbian]] characters Č, Ć, Ž and Š, respectively.<ref name="manual"/> The letter "Đ" is not present in the original version, so was commonly substituted with the [[Digraph (orthography)|digraph]] "DJ".
* The 64 codepoints from 128 to 191 (0x80 to 0xBF) are the 64 distinct 2×3 [[dot matrix|matrix]] blocks.<ref name="manual"/>
* Codepoints 64 (0x40) and 39 (0x27) are used for two-halves of the logo of one of two companies: Voja Antonić's MIPRO (whose logo is a [[Glider (Conway's Game of Life)|glider]] from [[Conway's Game of Life]]) or [[Elektronika Inženjering]] (whose logo is a stylized arrow). This logo is displayed in the "READY" prompt. EPROMs programmed by Antonić at ''Računari u vašoj kući'' offices use the MIPRO logo, while EPROMs produced at a factory use the Elektronika inženjering logo.<ref name="Vlado Vince">{{cite web |last1=Vince |first1=Vlado |title=Making a Galaksija computer FAQ |url=https://blog.vladovince.com/galaksija/ |website=Vlado Vince |date=18 April 2023}}</ref>

Each character is represented as a 8×16 matrix of [[pixel]]s. In this [[read-only memory|ROM]], 8-pixel rows of each character are represented as 8 [[bit]]s of one [[byte]].<ref>{{cite web |last1=Vince |first1=Vlado |title=Designing custom characters for the Galaksija |url=https://blog.vladovince.com/designing-custom-characters-for-the-galaksija/ |website=Vlado Vince |date=17 May 2023}}</ref>

{{Contains special characters|Uncommon Unicode|section=table}}
{| {{chset-table-header1|Galaksija character encoding<ref name="manual">{{cite book |last1=Ristanović |first1=Dejan |author1-link=Dejan Ristanović |title=Uputstvo za upotrebu računar "galaksija" |pages=5, 18 |url=https://emulator.galaksija.org/MagScans/index.html |language=sr}}</ref>}}
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== "Cassette" port ==
Galaksija used [[cassette tape]] as [[secondary storage]]. It featured a 5-pin [[DIN connector]] used to connect the computer to a cassette tape recorder. Tape interface circuitry was rudimentary – other than few elements controlling the levels it was essentially one-bit digital equivalent to the one in the [[ZX Spectrum]]. The input signal was routed to the [[integrated circuit]] otherwise responsible for keyboard, so the CPU would "see" the input signal as a series of very fast key presses of varying lengths and gaps between them.

It is normally stated that original Galaksija does not have any dedicated (separate) audio ports and most of the programs were written as silent. It was, however, possible to utilize the cassette tape port as an audio output as well like it is done in [[ZX Spectrum]] (its "EAR" connector). The only technical difference between ZX Spectrum and Galaksija in regards to existence of audio is that ZX Spectrum has a built-in beeper, while Galaksija's plans do not include any kind of a speaker.

== Software sharing via radio ==
In Autumn 1983, Računari's editor contacted [[Zoran Modli]], the DJ of [[Radio Belgrade 202]]'s [[Ventilator 202]] program, asking him to broadcast software as part of the show.<ref name="eurogamer" /> As the Galaksija stored software on [[Cassette tape#Data recording|data cassette]], Modli was able to alert listeners about an upcoming data broadcast, broadcast the data as sound over the regular FM wave  and listeners were able to record the data broadcast using home [[cassette deck]]s and load the software on the Galaksija via the data cassette drive. Ventilator 202 became a hub of software sharing, with home programmers editing previously broadcast software and sending in the edits for future rebroadcast.<ref name="Eby"/> Over three years Ventilator 202 broadcast 150 pieces of software for the Galaksija, the Spectrum and Commodore 64, including a digital magazine, named Hack News. Modli notes that while much of the software was written for the Ventilator 202 audience by Yugoslavian authors, plenty of those same authors were also [[Software cracking|cracking]], [[Video game piracy|pirating]] and [[File sharing|sharing]] commercial software via the show.<ref>{{cite web |last1=Modli |first1=Zoran |title=Ventilator 202 |url=http://www.modli.rs/radio/ventilator/ventilator.html |website=Modli |publisher=Zoran Modli |access-date=9 December 2022}}</ref>

== Design ==
To simplify "do-it-yourself" building and reduce cost, the [[printed circuit board]] was designed as single-layer (one-side) board. This resulted in a relatively complicated design requiring many component-side connections to be made using wire links.

Galaksija's [[computer case|case]] was not pre-built. Instead, the guide suggested it to be built out of the [[printed circuit board]] material (such as [[Pertinax (material)|Pertinax]]) also used for the [[mainboard]]. Thus, the top, sides and reinforcements were [[soldering|soldered]] together to form the "lid". [[Acrylic glass]] was recommended for the underside. The guide included instructions on cleaning, painting and even decorating the assembled case. The name "GALAKSIJA" and decorative border were to be added using [[Letraset]] transfer letter sheets after the first (white) coat of paint but before the second coat of final colour. After the paint dried, transferred decorations were supposed to be scratched off, exposing underlying white paint.

The keyboard is laid out such that keys have their own [[memory-mapped I/O|memory-mapped addresses]] that, in most cases, follow the same order as [[ASCII]] code of the letter on the key. This saved the ROM space by reducing lookup tables but significantly increased the complexity of single-layer keyboard [[printed circuit board|PCB]] such that it alone required 35 wire links.

== Gallery ==
<gallery mode="packed">
File:Galaksija 1984.jpg|Galaksija's mainboard, partly assembled
File:Galaksija Ready Prompt.png|Ready prompt at startup
File:Desktop computer GALAKSIJA, 1983.jpg|Later factory-manufactured Galaksija case
File:Galaksija home computer.jpg|A Galaksija at BalCCon2k14 Novi Sad, Serbia
File:Voja Antonic.jpg|Voja Antonic, inventor of the Galaksija
</gallery>

== See also ==
* [[History of computer hardware in Yugoslavia]]
* [[Galaksija BASIC]] – details about Galaksija's [[BASIC]] [[programming language]]
* [[Galaksija Plus]] – improved version of Galaksija, announced in Jun/July 1984 (6th) issue of "Računari" magazine ([[English language|in English]]: ''Computers'', renamed from "Računari u vašoj kući")
* [[Voja Antonić]] – the creator of Galaksija
* [[Dejan Ristanović]] – well known [[Serbs|Serbian]] writer and computer publicist who authored much of the special issue magazine featuring Galaksija
* [[Z80]] – Galaksija's [[CPU]]
*[[ZX80]] - Sinclair ZX80 which predates the Galaksija by 4 years and has a remarkably similar system design including using the Z80A to drive the video output.

== References ==
{{Reflist}}

== External links ==
{{Commons category|Galaksija}}

=== Articles ===
* [http://www.dejanristanovic.com/comp1.htm Computers in your home] – short overview by [[Dejan Ristanović]], the author of ''Računari u vašoj kući'' magazine issue (in English)
* [https://web.archive.org/web/20090504112705/http://www.paralax.rs/pr83.htm 1983: Galaksija] – how it all started, by Galaksija's creator [[Voja Antonić]] himself (in [[Serbian language|Serbian]])
* [http://www.dejanristanovic.com/rac1/rac1gal.htm Computer Galaksija] – detailed description of computer operation for those planning to build it, as published in the ''Računari u vašoj kući'' magazine issue. Written by creator [[Voja Antonić]] (in Serbian).
* [http://www.dejanristanovic.com/rac1/rac1umet.htm Uputstvo za upotrebu] – complete, original, user manual on-line (in Serbian)
* [http://retrospec.sgn.net/users/tomcat/Galaksija/MagScans/ Magazine Scans] {{Webarchive|url=https://web.archive.org/web/20190831123824/http://retrospec.sgn.net/users/tomcat/Galaksija/MagScans/ |date=31 August 2019 }} – scans of original magazine pages containing schematic diagrams, building and other instructions and programs for Galaksija (in Serbian)
* [http://www.dejanristanovic.com/galaks.htm Računar Galaksija] by [[Dejan Ristanović]], the author of ''Računari u vašoj kući'' magazine issue (in Serbian)
* [https://www.crowdsupply.com/rcc-productions/galaksija Crowd Supply Project] - Crowd Supply Project may offer another Galaksija

=== Presentations ===
* [https://events.ccc.de/congress/2012/Fahrplan/attachments/2250_prezentacija.pdf The Ultimate Galaksija Talk] - in-depth presentation by Tomaž Šolc given at the 29C3 conference

=== Remakes ===
* [http://galaksija.petnica.rs/index.php/ μGalaksija] – FPGA Galaksija
* [https://www.tablix.org/~avian/blog/articles/galaksija/ CMOS] – CMOS Galaksija

=== Emulators ===
* [http://solair.eunet.rs/~jovkovic/galaxy/ Galaksija Emulator] – original [[DOS]]-based [[emulator]] by Miodrag Jevremović (in Serbian)
* [http://www.galaksija.org/ Galaksija Emulator pages] – [[Microsoft Windows]] port of original [[DOS]] [[emulator]] (in Serbian)
* [http://www.mess.org/ MESS] – The open source multi-platform multi-system emulator [[MESS]] supports Galaksija
* [http://www.simcoupe.org/ Sam Coupé] — A Galaksija emulator running under [[Sam Coupé]]
* [http://galaksija.net/ GALe - Galaksija Emulator] - Emulates Galaksija in web browser.

=== Online museums ===
* [https://web.archive.org/web/20080930181518/http://www.old-computers.com/museum/computer.asp?st=1&c=330 Old-Computers.com Museum page on Galaksija]
* [https://web.archive.org/web/20070920220836/http://www.rkovac.com/index.php?id=48 Zgodovina] – an article in [[Slovene language|Slovene]]

=== Other ===
* [http://www.modli.rs/ Zoran Modli Home page] home page of [[Ventilator 202]] radio show host (in Serbian). Same site contains a [http://www.modli.rs/radio/ventilator/ventilator.html story of Ventilator 202 show], (also in Serbian).
* [http://www.theamphour.com/247-an-interview-with-voja-antonic-gerontogenous-galaksija-genesis/ #247 – An Interview with Voja Antonic – Gerontogenous Galaksija Genesis] An audio podcast interview with Voja Antonic about the creation of the Galaksija, in English.
* [https://revspace.nl/Galaksija/ galaksija info in English] {{Webarchive|url=https://web.archive.org/web/20220209134108/https://revspace.nl/Galaksija |date=9 February 2022 }} with reproduced schematics, and an English translation of the thesis document "about the CMOS implementation of the GALAKSIJA retro home build computer"

{{Serbian computers}}

[[Category:Galaksija (computer)| ]]
[[Category:Home computers]]
[[Category:Serbian inventions]]
[[Category:Z80-based home computers]]
[[Category:Computer-related introductions in 1983]]