Oxford Trivia corrupt cart fix, Pascal?

[Martin_Head]

OK. So I have copied and pasted the bad data blocks from the RWAP games image (Which happens to be a QLAY image rather than a Qemulator image) to the dump image. And repurposed two unused sectors for the missing ones.

I tried the Mdump game image, I got the screen asking for the original MDV. I pressed "y". And I think the MDV light came on for a moment, Then nothing. The system just hung.

I don't know if there is a problem in my copying and pasting, of if some copy protection is coming in.
chr$, does the copy you have look like a master, or a working copy?

So I decided to have a look at the questions image files.
in the directories, chr$ copy has has about 20 files, with names like MUSIC, SPORT, HISTORY etc. With 4, maybe 5 bad sectors.
The RWAP copy has 5 files, BACKUP, and FILES 1 to 4.

So I don't know if we have two different versions of the game. (So my copying and pasting from one to the other could be a big problem)
Or one is a master, and one a working copy. And the various categories need to be extracted.

And that was about as far as I got .

[Chr$]

OK. So I have copied and pasted the bad data blocks from the RWAP games image (Which happens to be a QLAY image rather than a Qemulator image) to the dump image. And repurposed two unused sectors for the missing ones.

I tried the Mdump game image, I got the screen asking for the original MDV. I pressed "y". And I think the MDV light came on for a moment, Then nothing. The system just hung.

I don't know if there is a problem in my copying and pasting, of if some copy protection is coming in.
chr$, does the copy you have look like a master, or a working copy?

So I decided to have a look at the questions image files.
in the directories, chr$ copy has has about 20 files, with names like MUSIC, SPORT, HISTORY etc. With 4, maybe 5 bad sectors.
The RWAP copy has 5 files, BACKUP, and FILES 1 to 4.

So I don't know if we have two different versions of the game. (So my copying and pasting from one to the other could be a big problem)
Or one is a master, and one a working copy. And the various categories need to be extracted.

And that was about as far as I got .

I'm fairly certain that the 'game' cart is an original.

The questions cart could be made up as it certainly includes a lot of categories and I did think that originally it came with just 5 or so. mdump_task reported problems with files MUSIC, SPORT, HISTORY, CINEMA, here's the mdump screen:

The question files don't appear to be plain text, looks more complicated than that.
This page shows the carts and also scans of the manual, which seems to imply that it checks something from the original, once you've started in with a backup.
https://qxl.win/oxford_trivia.htm

[Chr$]

I wonder if the game cart only requires the bad 3 sectors of TRIV_3g_PEXE as reported by Cartridge Dr ($0A, $1A, $3B). Could the 2 missing ones be deliberate?

[Andrew]

I wonder if the game cart only requires the bad 3 sectors of TRIV_3g_PEXE as reported by Cartridge Dr ($0A, $1A, $3B). Could the 2 missing ones be deliberate?

I had no time to look at the microdrives at sector level, but I have the game running in QEmulator:

1. Place RWAP copies in mdv1 and mdv2
2. Start QL
3. the screen "Place the Original in drive 1" appears

4. Place Original copy in mdv1. As soon as the original is loaded and you press Y or N the game starts.

5. After game start it makes no difference what cart is in mdv1_

Observations:
1. The Original is labeled "Triv Game" while the RWAP copy is labeled "Game"
2. At step 4 the game does not read or load any game data from the microdrive - it only checks for the existence of the copy protection
3. If you copy anything on Original the copy protection is destroyed - that makes me believe that the copy protection resides in some sectors that are marked as free or it checks the number of free sectors

I am not sure if any of these is of interest

[Chr$]

No! I'm sure I tried that particular combination.

Right, having late lunch and will then give it a go.

[Chr$]

Yes, that worked for me too!

Sorry to have wasted your time Martin.

I wonder how the other question categories (on my dump of my own questions cart) come in to play, or if my questions cart is from something else entirely!

Instead of the RWAP questions cart I tried the same procedure with the questions dump and that fails with the PASCAL ABORT error (that must have been what I tried before). The question files on the RWAP cart has files named FILE1, FILE2 etc (and each is 20,480 bytes in size), whereas my dump has lots of question categories with descriptive names, e.g. HISTORY, SCIENCE etc and with varying file sizes.

Searching text in the dumps, I can find references to mdv2_file1 (and the others) in both my dump of the 'game' cart and in the RWAP version, but I can find no references to the category names that are also the file names on my dumped questions cart.

I suppose that probably means that my questions cart is from something else entirely.

[NormanDunbar]

I've not been playing close attention, but is it possible that the executable reads the directory of the questions cartridge, looking for filenames to load? Thinking about those files which are not named "file1" etc.

Apologies for the noise, if I'm way off base. Again!


Cheers,
Norm.

[Chr$]

I've not been playing close attention, but is it possible that the executable reads the directory of the questions cartridge, looking for filenames to load? Thinking about those files which are not named "file1" etc.

Apologies for the noise, if I'm way off base. Again!


Cheers,
Norm.

I thought that too, but both my dump of the original and the mdv file from RWAP specifically refer to mdv2_FILE1, FILE2, FILE3 and FILE4 so I think it must expect them to be there with those names.

Also, looking at the data on my questions cart dump, it appears totally different. I can also see some lines of superbasic, which seem to refer to file names that have nothing to do with Oxford Trivia, e.g.

MERGE mdv1_msetup
MERGE prog$&'_mquiz'
MERGE prog$&'_analyse and
LBYTES prog$&'_mdata',sqaddr

mquiz? msetup?

I think it was a red herring and it's a question set from another program - that I have not been able to identify.

[Andrew]

The question files don't appear to be plain text, looks more complicated than that.

It's compressed plain text, with some sort of a header, with a very simple compression scheme: all characters over 128 represent a group of 2 or 3 characters.
I have not checked all files, but for the file "people" the mapping is like this:

chr$(136) = ma
chr$(149) = ght
chr$(171) = ite
chr$(175) = ess
chr$(177) = ard
chr$(190) = en
chr$(211) = ie
chr$(201) = of
chr$(205) = an
chr$(206) = am
chr$(207) = ar
chr$(214) = ll
chr$(215) = ia
chr$(223) = d_ (d and space)
chr$(224) = n_ (n and space)
chr$(227) = t_ (t and space)
chr$(230) = pi
chr$(237) = be

[M68008]

Based on Andrew's experiment, the two versions of the cartridge seem compatible as far as the copy protection goes.

I should be able to merge them into a single working master copy.