BM: Hello, Stefan, you are a well-known person in Atari 8bit community thanks to your software products which became very popular. Would you mind to answer some questions, resp. be interviewed by us?
SD: Hello, no problem. By the software you mean QMEG. It spread over the world. What would you like to ask?
BM: Of course, QMEG is most popular. Many 8bit users have this interesting OS. It somehow appeared in our country. But how it begun? And was it distributed officially here in Germany?
SD: Well, I made it simply to use extra RAM and other Atari HW more efficiently. But people from COMPY SHOP liked it and have been selling QMEG 3 officially. They sold, I think, around 50 pieces. But then QMEG spread all over the world. I think many users are in Poland.
BM: OK, it was version 3 and what about version 4?
SD: I made version 4 in 1997 for me and my friends. ABBUC distributed it and sold something like 30 pieces.
ZB: So QMEG is not a commercial product? You do not hate people who use QMEG without paying for it?
SD: No, I don't hate people using QMEG for free. It is available on some internet sites and archives and I do not have anything against it.
BM: That's nice. But in that case I am surprised there is no official web site for QMEG. Why such a popular product which can be freely distributed has not its own page?
SD: Well. It is a bit complicated. I do not require money for the work I did. But QMEG is still based on original OS, which was copyrighted. QMEG is just patched Atari XL OS. And I do not want to risk any problems with lawyers.
BM: OK, I understand this. But I think QMEG would desire at least an info page with documentation. Right now I write an article about QMEG 3 and QMEG 4 for our Flop magazine. There is a Czech documentation only for QMEG 3 so many Czech users does not know the great new functions of the 4th version. I looked for a QMEG 4 manual in English but I found only a German version with some English notes.
SD: Yeah. It is possible that there is only German version. But it should not be a problem to translate it to English. I can do that. After it is finished I will put it to some English Atari web.
BM: That would be great. Thank you. Could you please shortly describe the differences between version 3 and 4?
SD: Hmm, I will try. But I did not use QMEG 3 for 20 years, so I am not sure if I can remember all the differences. First, as you can see in the menu, there are all 8 drive numbers. Another thing is, that QMEG 4 recognizes floppy drive speeders automatically, so you do not need to press U. And another new feature is the CAS simulator.
BM: One of the new functions is freezer, but very few people know how to use it.
SD: It is simple. Let's start a program. Now, any time, I press Control + Help and it freeze. Then I can press Control + S and RAM is saved to RAM disk A. Now I press Control + Help again and the application continues. If I would like to return back to the saved position, I freeze the program again. Then I press Control + L to load the saved memory. And after Control + Help, it runs from the saved position.
BM: Wow! That sounds really good. Does it work with all programs?
SD: Well there could be some problems if the application (e.g. a game) uses hardware registers because those are not saved in RAM. And programs that switch off operating system cannot use this freezer. But I cannot forget to mention another QMEG Freezer feature which I like. When frozen, you can type 6 hexadecimal numbers followed by Return. First 4 digits are memory address. The last 2 represent the value you want to write to that address. Thus you can change anything in the running program. For example a background color.
BM: Or you can patch a game to unlimited lives, can't you?
SD: Oh yes, you can, if the game is compatible with QMEG freezer.
ZB: And what about printers? There was a support for CENTRONICS printers in QMEG 3. Is it still in QMEG 4?
SD: Oh no. I had to remove it. Since 90s it was easier to print from PC so I did not need printer support in my Atari any more. I needed the space in ROM for new features. Like the freezer. It takes a half KB in the OS.
ZB: And what types of CENTRONICS s interfaces did QMEG 3 support?
SD: I am not sure if I understand your question but we made a parallel interface using extra PIA chip in the Atari. It was put upon the original PIA with energy pins soldered to it. All other pins (normally used for joystick ports) were bended up. They were connected to a canon 25 mounted on the rare panel of Atari. You can see the hole which remains in my Atari case after I removed the connector.
BM: Wow, so this is physically the Atari machine you used those times you developed QMEG?
SD: Oh yes, this is my original Atari 800 XL. I have it now for 36 years and it still works without problems. I developed QMEG and all my other software on it.
ZB: Nice, but back to printers. So you did not modify QMEG 3 to use the CENTRONICS interface with Intel 8055 compatible chips?
SD: No. I did not know there were some other interfaces build for Atari.
ZB: Oh yes. It was not possible to buy Motorola chips in our country until 1990, so other technologies were used. I think the CENTRONICS based on Intel was developed in Slovakia. And then it was used in our country with a patched QMEG 3.2.
SD: Well, it is surprise for me, but yes. It should be possible to patch QMEG to support such interface.
BM: QMEG means Quarter Mega, so 256 KiB. I always wondered why it is not possible to have 2 medium RAM disks in QMEG when they would fit within 256 KiB. So how much extra memory can QMEG really use?
SD: QMEG uses 192 KiB of extra RAM. 256 KiB means 64 KiB of operating RAM plus 192 KiB of RAM disk.
BM: Why 192 KiB RAM disk? I did not heard about such expansion. Everyone I know has 256 KiB or more extra memory.
SD: 192 KiB memory expansion was the first expansion made. It was popular in 1980s because it is very easy to build. You simply replace the original memory chips in Atari with the chips of four times bigger capacity and add a few control chips and that's it. You have 64 KiB operating RAM and 192 KiB RAM disk.
BM: OK, 1980s, it was QMEG 3. But in 1990s when QMEG 4 was released, 256 KiB and larger expansions were available and used. So why QMEG 4 does not support at least 256 KiB RAM disk?
SD: Well, I see no need for this. I have 192 KiB extra RAM in my Atari and it is enough for me. What would be the advantage? To have 2 medium disks in RAM disk at once? Why? Nowadays nobody boots multidisk games from RAM disk. Everybody uses fast USB or SD floppy emulators. And for copying a disk it is enough to load one at a time.
BM: OK, that make sense. Till now we talked about QMEG 3 and 4. But what about versions 1 and 2?
SD: Oh, it is a long time. I am not sure if I still have some of them. It is 30 years. Well, QMEG 1 was not hardware. I mean not in ROM. It was loadable. But QMEG 2 was in ROM. B
BM: What plans do you have for the future? For example will there be QMEG 5?
SD: Well, nothing special. May be I can make new levels for my Hugohunt game. And I work on YDOS, the successor of XDOS. I don't think there will be a new version of QMEG. I used all space available for the operating system so for new functions I would have to remove some current functionality.
BM: OK, you mentioned some of your other projects, like games. You also developed games? Which ones?
SD: Yes, it was long time ago. I wrote them in Basic. I can mention Hugohunt. It is a logical game and was also ported to Commodore. Another game is Der Huerdenlaeufer (Hurdle Jumper in English) where you go down a hill and have to jump over hurdles.
BM: Yes, those are nice simple games. But you are mostly know thanks to your system tools. I have seen you using a program called YASH. What is it?
SD: YASH is complex tool for SIO2USB - the floppy emulator which stores software on USB flash disk and internal memory. Although SIO2USB has a display and several buttons, you can control just basic functions with them. YASH is a file manager, can mount/unmount ATR files, create directories, copy files, set time (in the device), show free memory, format USB drive etc.
BM: Very nice. And you also wrote alternative firmware for XF 551 drives. What advantages it brings? Can I for example use a diskette formatted as 2 separate sides as 2 disks without physically turning the diskette?
SD: Well, it is also 20 years ago. I cannot remember all the functions. But you can switch between 8 operating modes. One of them is standard mode. It handles 1 diskette as 1 DS/DD disk.
What you ask is the partition mode. You can handle one diskette as 2 independent partitions. If you have your drive set to number 1, the second side is accessible as drive 2.
BM: Hmm, that sounds great. I know it is also possible to use 3.5" drive in XF551 with your firmware.
SD: Yes. There is another mode where you can read ST or PC diskettes. But for more information you have to look to the documentation. Unfortunately it is only in German.
BM: You also mentioned X-DOS. Is it just another DOS? What functions it has?
SD: X-DOS is a command line DOS. It uses as low memory as possible and it has capability of loadable drivers, which was not easy to implement. Not long ago I released X-DOS 2.5.
I removed XF-551 build-in functions. Instead, I added support for some emulators, so X-DOS can now be used with Altirra. And the map command is now internal. It is used to analyze executable files - prints the addresses etc.
BM: How do the loadable drivers work?
SD: You just write the name and parameters to command line and press Return. For example here is a driver for commented errors. It not just show the error code, but also the explanation of it. Like ERROR 170 - File not found.
Creating a new driver is easy. I can show you the code of the background color driver. It changes the color to what you desire and remembers the original one. So after you unload the driver it will restore the previous color.
BM: And what types of file systems does X-DOS handle?
SD: Only standard Atari DOS 2/3 disks are supported. No SpartaDOS etc.
BM: Thank you, Stefan, for your time and the interesting information. Also thank you for all the useful Atari software you made, especially for QMEG.
SD: You are welcome.