Orao (computer)

Orao
	Orao
Type	Home computer
Generation	8-bit
Release date	Yugoslavia: 1984
Lifespan	1984–1991
Discontinued	1991
Media	Cassette tape; Floppy disk
Operating system	Orao BASIC
CPU	MOS Technology 6502 at 1 MHz
Memory	16 KB / 32 KB
Display	RF modulator (video)
Sound	internal speaker (audio, early models) or three-channel audio via RF modulator (audio, later models)
Predecessor	Galeb (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+.

History

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

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

Since the Orao was not compatible with any home computer of the time, its software offering was scarce due to the lack of software companies whose products supported the platform.

Lack of capabilities

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

Architecture

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.

Specifications

Back of the case, with connectors.

CPU: MOS Technology 6502 at 1 MHz
Read-Only Memory: 16 KB (with BASIC interpreter and Machine code monitor)
RAM: 16 KB (expandable to 32 KB)
VRAM up to 24 KB
Graphics: monochrome 256×256 pixels, in up to 8 shades of gray
Text mode: 32 lines with 32 characters each
72 chars in one BASIC line
Sound: single-channel, 5 octaves through built-in loudspeaker
Computer keyboard: 61-key QWERTZ
I/O ports: video and RF TV out, cassette tape interface (DIN-5), RS-232 (D-25), Edge expansion connector
Peripherals: 5.25" floppy drive, Printer
Price: 55,000 dinars planned but increased to 80,000 during production

BASIC example

Math

10 REM PLOTS ONE PERIOD OF SINUS GRAPH 20 for x=0 to 128 30 y=64*sin(3.14159*x/64) 40 plot x,y+96 50 next 60 END

Physics

 5 REM CONVERTS KM/H TO M/S  10 PRINT"KM/H M/S"  20 FOR SP=0 TO 60  30 PRINT SP,SP*1000/(60*60)  40 NEXT

Output

RUN KM/H M/S  0 0   1 .277777778   2 .555555556   3 .833333333   4 1.11111111   5 1.38888889   6 1.66666667   7 1.94444445   8 2.22222222   9 2.5   10 2.77777778   11 3.05555556   12 3.33333333   13 3.61111111   14 3.88888889   15 4.16666667   16 4.44444445   17 4.72222222   18 5   19 5.27777778   20 5.55555556   21 5.83333334   22 6.11111111   23 6.38888889   24 6.66666667   25 6.94444445   26 7.22222223   27 7.5   28 7.77777778   29 8.05555556   30 8.33333333   31 8.61111112   32 8.88888889   33 9.16666667   34 9.44444445   35 9.72222223   36 10   37 10.2777778   38 10.5555556   39 10.8333333   40 11.1111111   41 11.3888889   42 11.6666667   43 11.9444444   44 12.2222222   45 12.5   46 12.7777778   47 13.0555556   48 13.3333333   49 13.6111111   50 13.8888889   51 14.1666667   52 14.4444444   53 14.7222222   54 15   55 15.2777778   56 15.5555556   57 15.8333333   58 16.1111111   59 16.3888889   60 16.6666667

Machine code/Assembly example

 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

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

References

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

External links

[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.

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