Tips for Reverse Engineering a Cassette Program

[srowe]

I still get a ?LOAD ERROR with this .tap file.

[orion70]

I can load the TAP file correctly with 8K+ RAM.

[srowe]

I can load the TAP file correctly with 8K+ RAM.

Weird, is that with a PAL configuration?

Code: Select all

[srowe@gilraen boss-chess]$ unzip ~/Downloads/BOSS-8k.zip       
Archive:  /home/srowe/Downloads/BOSS-8k.zip
  inflating: BOSS-8k.TAP             
[srowe@gilraen boss-chess]$ xvic -memory 8k -1 BOSS-8k.TAP

Followed by LOAD gives me

[vicist]

I had the same problem.
Used Tap-Clean on the file and that did the trick.
Now loads OK at warp in vice.

[srowe]

Could you attach the cleaned .tap file?

[vicist]

Sure....

cleaned_BOSS-8k.zip

(421.78 KiB) Downloaded 49 times

[srowe]

I still get a ?LOAD ERROR, even with this copy.

[orion70]

Why don't you just use winvice instead of the command line vice? If you are a Linux user, WinE will easily run windows executables.

[vicist]

Tap-Clean reports errors after cleaning but it still works.

Using load will produce a 'LOAD ERROR'.
Using 'shift RUN/STOP' works.

Don't ask me why.

[orion70]

Yep drag and drop into the vice window will in fact emulate a shift+run.

[srowe]

Tap-Clean reports errors after cleaning but it still works.

Using load will produce a 'LOAD ERROR'.
Using 'shift RUN/STOP' works.

Don't ask me why.

If you see "LOAD ERROR" then the KERNAL has detected long/short blocks and/or checksum errors. Whatever is loaded is corrupt in some way. RUN/STOP only "works" because it rams the characters "LOAD<CR>" "RUN<CR>" into the keyboard buffer, it doesn't magically fix anything.

[vicist]

No, no magic...

...and yet it works.

[nbla000]

Yes, it seems that works even if there is a "?LOAD ERROR" but maybe will be problems in a certain condition of the game or something else who knows.

Btw I've tried to create a prg file from both original/cleaned tape but each time it will produce a prg (from $1201 to $3FFF) with different CRC32, it works but I don't trust it.

By filling memory from 1201 to 3fff with an arbitrary value before to load the TAP, you see these value inside this range 1201/3ff and not always in the same place, for me a new dump is better.

[groepaz]

Why don't you just use winvice instead of the command line vice?

there is no such thing as a "command line vice". winvice can be started using the exact same commandline.

[orion70]

Ok, i meant "launch the program dragging it into the window".