MSX1/CAS software not working on Turbo R GT

By -Neo-

Champion (396)

-Neo- さんの画像

15-10-2016, 22:46

Hi all,

I have several CAS files that won't run on my Turbo R GT. I use an MFR SD SCC+. Examples are Auf Wiedersehen Monty and Avenger. They come from the TOSEC archive. There are also several CAS files that do work. Is this a known problem and can I fix it somehow?

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By Louthrax

Prophet (2413)

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16-10-2016, 00:28

The CAS emulation on MSX can't be perfect sadly... Lots of games are replacing the BIOS page or doing direct cassette ports access, which are breaking the "emulation routne". So yeah, that's a known problem, with no real solution for now (except patching the .cas images).

There's also an MSX 1 emulator from Nyyriki (turboR only) that allows to load .cas images IIRC, never tried that but it might work.

By dink

Expert (73)

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16-10-2016, 03:50

A simple way to get around cas issues is to find the dsk version of the same thing. Grab the TOSEC MSX1 collection and you will have them. Also, to make matters easier, the dsk files can be converted to rom using "dsk2rom -fc 1 abc.dsk abc.rom", for example. use google for TOSEC MSX1 and MSX DSK2ROM for links.

best regards,
- dink

By gdx

Enlighted (5364)

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16-10-2016, 08:16

Converting a DSK to a ROM brings no interest to run a game on Turbo R. We can launch the DSK directly with RUNIT or HDDEMU. Anyway, the best alternative is to extract the files to a folder on your SD card and run it directly.

By NYYRIKKI

Enlighted (5918)

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16-10-2016, 11:07

Yes indeed this is a known problem, but it is not directly related to storage format at all. ie Auf Wiedersehen Monty crashes simply because it searches RAM from slot 0 but forgets to restore the subslot register after the search... This causes it to fail on all computers that have expanded slot 0 (= mostly on MSX2 and better machines) I've seen this same RAM search code on many other MSX cassette games as well such as Gauntlet or Bounder and it is just faulty from the factory... I think there has been some faulty example code floating around that has ended up in to major number of early MSX cassette releases.

The reason why disk versions might work better is that they are cracked from cassette versions... With a bit of luck this means that someone who has already MSX2 or better has copied it to disk and fixed the code... or at least changed it to work in his own MSX model.

Louthrax wrote:

There's also an MSX 1 emulator from Nyyriki (turboR only) that allows to load .cas images IIRC, never tried that but it might work.

Louthrax means this one... CAS-format it self is not fool proof and can't store every game, but this is rarely the problem. Also rMSX can load practically all CAS-files perfectly... or at least just the same way as fMSX does (CAS-file format originates from this emulator) How ever because it loads exactly what is written to the CAS-file and it emulates MSX1 with expanded slot 0, the result is a hang up when it runs a program with compatibility problems as I described.

There is anyway one program from Martos that tries to cope with the bad code (CASRUNX ??? I'm not really sure about the name) It tries to find faulty patterns from the game code and tries to patch it to work better... How it works depends heavily from the game in question. The solution of altering data on the fly based on pattern recognition is controversial at best, but I've heard that at least Auf Wiedersehen Monty starts to work with this loader. Naturally best would be if there would be active hobbyists that would release compatibility patches for each of these old CAS-games, but it would be too huge job for any individual to solve, so this is the reality we need to live with for now.

By Louthrax

Prophet (2413)

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16-10-2016, 11:43

Also, there was a Brazilian (maybe Spanish ?) site offering lots of good-quality ROM conversions of cassette games. Can't retrieve it right now... Darn, where is it ??

By -Neo-

Champion (396)

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16-10-2016, 12:15

Thanks for your input till now all, appreciated.

I do have for some games the DSK files from TOSEC. However, they also hang my Turbo R which is in line with what Nyyrikki is explaining I guess. Would be great if you can find and point me to that site with good ROM conversions.

By gdx

Enlighted (5364)

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16-10-2016, 13:18

Sadly, the DSK files from TOSEC contain the instruction POKE255,170 (or POKE &HFFFF,&HAA) that hangs many MSX.
You must replace this instruction by POKE-1,(15-PEEK(-1)\16)*17.

By -Neo-

Champion (396)

-Neo- さんの画像

19-10-2016, 03:11

Thanks gds, but didn't work for Avenger. Contains some DEFUSR statements and bloads. I noticed a lot of DSKs don't work. ROMs work mostly.

By Louthrax

Prophet (2413)

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19-10-2016, 04:55

So I've retrieved on my HD a zip with all cassette games converted to ROMs I mentionned above. It has 119 ROMs, and starts with 3DPOOL.ROM, 180.ROM, ABSIMBEL.ROM... Would be nice to rename them to long filenames to launch them with SofaRun. Those interested by this file can PM me.

Still no way to retrieve the site that was offering those conversions. I just remember it had a black background, snapshots of each game, and was Spanish or Brazilian...