My old PRAVETZ 8D (ORIC ATMOS)

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rax
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My old PRAVETZ 8D (ORIC ATMOS)

Post by rax »

Hello :)

I had promised the ISS to shoot my old modified PRAVETZ 8D (ORIC ATMOS).
I decided to make a short video and share my mod from 1994 year with you.

The computer has added EPROM 27512 (64k) and modified ROM. There is a real RESET button connected directly to the processor. After pressing the RESET (the program of $ F88F is changed) and does something like a warm reset (initializes the text mode and some settings) checks if there is a floppy disk controller and upload DOS-8D in the RAM EVERY TIME. There is a reset vector added to $ 237. When 0 goes to it and presses RESET, the computer does a real reset. Here are the programs that are built into the additional EPROM:

- Editor (text editor)
- PTM (print program in text mode)
- Super Print (print program in graphic mode)
- Monitor (Apple-like monitoring program)
- Disk Fixer (program for processing tracks and sectors on floppy disks)
- BASIC Helper
- Copy (disk copy program)
- Lat (Latin characters)
- Organ (music program)
- Tetris (game)

1. Edit - A program for processing text files. Powerful tool similar to E2 for PC.

2. PTM - a program for printing text on a printer. Uses the text mode of the printer.

3. Super Print - Program for printing in graphic mode. Supports multiple saw text styling, alignment and fonts. There are 10 built-in fonts in the EPROM, the others are loaded from a floppy disk drive.

4. Monitor - Monitor program. This program is equivalent to the MONITOR program for APPLE 2

5. Disk Fixer - With the help of this program you can manipulate the sectors directly on the floppy disk drive.

6. BASIC Helper - manipulates BASIC programs - renumbers, deletes lines from-to, searches for a variable or service word, removes unnecessary spaces.

7. Copy - This is a small BASIC program that can copy entire floppies and check that individual paths are read correctly.

8. Lat - This is just a font. Pravetz 8D has no lowercase or uppercase Latin letters (there is only uppercase Cyrillic and uppercase Latin). In toast programs, the texts are lowercase and uppercase in Latin.

9. Organ - Small BASIC music program.

10. Tetris - The game.


Last edited by rax on Tue Jan 05, 2021 3:03 pm, edited 1 time in total.
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Dbug
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Re: My old PRAVETZ 8D (ORIC ATMOS)

Post by Dbug »

I like the double reset idea, I always wanted to have an easy way to swap between multiple differents ROMs, like the standard Oric rom, and one with utility programs that could be used to break into a game, dump data, examine memory, etc... :)
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Re: My old PRAVETZ 8D (ORIC ATMOS)

Post by ibisum »

Hey. cool setup .. EDIT looks like something that would be handy to have in a DEVTOOLS.DSK, *ahem* ..

These tools look pretty neat - did you write them?
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Re: My old PRAVETZ 8D (ORIC ATMOS)

Post by Dbug »

What would be required to have a working system where you basically boot on a custom rom with whatever you want in it, like a menu, small utilities, etc... and a way to either launch normally on Oric BASIC 1.1 or boot on the floppy drive?
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rax
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Re: My old PRAVETZ 8D (ORIC ATMOS)

Post by rax »

ibisum wrote: Tue Jan 05, 2021 7:52 pm These tools look pretty neat - did you write them?
No. They are written by other people. In those days there was a lot of amateur Bulgarian software.
Programs from 1 to 8 are required for a DEVTOOLS.DSK :), but unfortunately most of them only work with DOS-8D.

Dbug wrote: Tue Jan 05, 2021 8:11 pm What would be required to have a working system where you basically boot on a custom rom with whatever you want in it, like a menu, small utilities, etc... and a way to either launch normally on Oric BASIC 1.1 or boot on the floppy drive?
This system is just that. The modified ROM is a fully functioning BASIC 1.1 with several modifications. As far as I remember the changes are as follows:
- The RESET button is real and has no secondary vector, ie. leads directly to the ROM. That way, it can't crash or restart the computer. (there is no program I can't get out of :) )
- A driver has been added to detect the additional EPROM and call up the Menu routine (download routine to #8400 and call).
- If a floppy disk controller is turned on, DOS-8D is transferred to the RAM. (I have never booted DOS from a floppy disk :) ).
- There is a mechanical SWITCH that, if turned off, is not allowed to use the additional EPROM.
- Changed default color, ink, keys speed and etc.
- In the original ROM the subroutines for generating the alternate character set and displaying the welcome text when the computer is started have been removed. There is added the Driver to manage the additional EPROM.

In order to be able to use EPROM 64k, several hardware modifications have been made. Used port B5, B6, B7 form VIA (IC 6522) to control additional EPROM. Since port B7 is used for recording on a cassette player, this Prawetz 8D (Oric) can no longer record on a cassette, but only read.

Any programs can be added to the additional EPROM (as long as they are 64k - the size of the routine menu), but the routine Menu must be changed.

The things described are i'm not sure if they are 100% correct. 25 years have passed since then :).
Last edited by rax on Wed Jan 06, 2021 1:10 pm, edited 2 times in total.
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