[Coco] Zaxxon on disk from DataSoft can be made to run in MESS

[Robert Gault]

The game Zaxxon was recently mentioned here. The question was whether it 
could be transfered to disk. I don't have the tape version but do have 
the disk version by SEGA, released by DataSoft Inc., licensed to Tandy.

As stated previously the disk is highly copy protected and can't be 
backed up on a Coco. The copy protection consists of using sectors of 
512 bytes and non-sequential values up to 31. The game itself attempts 
to read one of these sectors after starting.

I transfered all of the game sectors to a standard disk, converting the 
512 byte sectors to two 256 byte sectors. The read sector routine was 
changed to a "legal" sector number. Zaxxon will now run in MESS.

MESS has the option to use for a Coco joystick either the PC arrows, PC 
mouse, or PC joystick. Zaxxon is almost playable using the arrows or 
mouse but not at my age. ;)  A PC joystick will almost be mandatory but 
the game will run.

If anyone gets official permission from the copyright holders to release 
this game, I can post the .dsk image. If permission can't be obtained, 
those who have the ability to read the disk and alter ml code, should 
have enough information to create a working copy from this and previous 
messages.