Orao (computer)

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Orao-IMG 7278.jpg
TypeHome computer
Release dateYugoslavia: 1984
MediaCassette tape
Floppy disk[1]
Operating systemOrao BASIC
CPUMOS Technology 6502 at 1 MHz
Memory16 KB / 32 KB
DisplayRF modulator (video)
Soundinternal speaker (audio, early models) or three-channel audio via RF modulator (audio, later models)
PredecessorGaleb (computer)

Orao (en. Eagle) was an 8-bit computer developed by PEL Varaždin in 1984. Its marketing and distribution was done by Velebit Informatika. It was used as a standard primary school and secondary school computer in Croatia and Vojvodina from 1985 to 1991.

Orao (code named YU102) was designed by Miroslav Kocijan to supersede Galeb (code named YU101). The goal was to make a better computer, yet with less components, easier to produce and less expensive. The initial version, dubbed Orao MR102, was succeeded by Orao 64 and Orao+.


The chief designer of Orao was Miroslav Kocijan, who previously constructed the basic motherboard for Galeb (working name YU101). Galeb was inspired by computers Compukit UK101, Ohio Scientific Superboard and Ohio Scientific Superboard II which appeared in the United Kingdom and the United States in 1979 and were cheaper than the Apple II, Commodore PET and TRS-80. Driven by the challenge of Anthony Madidi, Miroslav Kocijan began to develop a computer that is supposed to be more advanced than the Galeb with fewer components, easier to produce, better graphics, performance and a more affordable price. The working title of the new project was YU102.

Miroslav Kocijan managed to gather around him a group of people who helped in the development of electronic components and software. Kocijan had the idea to commercialize Orao, and was able to convince Rajko Ivanusic, director of PEL, to support the idea. In the market of the former Yugoslavia, where the purchase of home computers were disabled due to high tariffs and due to the low purchasing power of citizens and schools computers were unattainable, the idea of mass-produced home computers made sense.[2]

Serial production and price[edit]

The price of Orao was originally set to be around 55.000 Yugoslav dinars, however the price rose to 80.000 dinars. The production began in the summer of 1984. Since the only imported components were integrated circuits which were hard to acquire in Yugoslavia because of strict monetary politics, PEL Varaždin itself financed the imports of these components, which enabled a cheaper final product. Occasional problems that occurred in the serial production were related to the construction of certain external parts and overheating.

Lack of supported software[edit]

Considering Orao was not compatible with any computer of the time, software offering was lacking due to the lack of software companies whose products supported the platform.

Lack of capabilities[edit]

That was one of most common sentences related to 8-bit school computer. Result of that statement is chapter above.


The graphics were controlled by a special circuit, not by the main processor as it was the case in many other home computers because Kocijan's intention was to create a graphical computer similar to Xerox Alto, or Macintosh, and as such, he had it utilize bitmap graphics. The resolution was 256x256 dots, for up to 196,608 bits of VRAM as the graphics could need no more than three bits per pixel. Such a resolution was chosen for square dots, which enabled easy writing of graphical programs. The resolution of text was 32x32, and every character was rendered in an 8x8 field. The designers of Orao went an additional step further to create a computer which could be far more easily expanded, connect with a printer and establish a net connection through RS-232.


Back of the case, with connectors.

BASIC example[edit]

20 for x=0 to 128
30 y=64*sin(3.14159*x/64)
40 plot x,y+96
50 next
60 END

Machine code/Assembler example[edit]

 1000 A9 7F         LDA #7F
 1002 85 E2         STA  E2    ; x center
 1004 85 E3         STA  E3    ; y center
 1006 A9 6F         LDA #6F
 1008 85 F8         STA  F8    ; radius
 100A 20 06 FF      JSR  FF06  ; draw circle
 100D C6 E2         DEC  E2    ; decrement x center
 100F C6 E3         DEC  E3    ; decrement y center 
 1011 A5 F8         LDA  F8    
 1013 38            SEC 
 1014 E9 04         SBC #04    ; reduce radius for four points 
 1016 85 F8         STA  F8    ; store it
 1018 C9 21         CMP #21    ; compare with 0x21
 101A B0 EE         BCS  100A  ; bigger or equal ? yes, draw again
 101C 60            RTS        ; no, return

Design team[edit]

  • Miroslav Kocijan
  • Branko Zebec
  • Ivan Pongračić
  • Anđelko Kršić
  • Damir Šafarić
  • Davorin Krizman
  • Zdravko Melnjak
  • Vjekoslav Prstec
  • Dražen Zlatarek


  1. ^ Kristian Benić (30 August 2010). "Kompjutori u školama Jugoslavije" (in Croatian). tportal.hr.
  2. ^ "Miroslav Kocijan – pionir hrvatskog računarstva" (in Croatian). ZG-magazin. 15 February 2013.

External links[edit]