Exit to error: Corrupt MCB chain
Press enter to continue
Tested this on the latest SVN 4358.
Reproduce by:
1. Run GRAPHSET.EXE then choose: 4 - EGA (IBM Enhanced Graphics Adapter)
(all other modes work fine)
2. Run MM.EXE,
3. On intro screen press ALT-Q to quit.
Is this the game itself ?
M&M1 has a bug with its EGA display mode where it allocates a memory block that is too small for the data written into it, thus overwriting the following MCB header, and SVN catches it when the program terminates where 0.74 does not. In real DOS you get a message like "Memory allocation error, cannot load COMMAND.COM, system halted" -- SVN just has a different way of handling the situation, but 0.74 is left in an unstable state with a corrupt MCB chain.
Searching for BB 34 08 in the main executable finds where the game allocates the memory block for Tandy graphics. Searching for BB 78 05 finds the equivalent code for EGA graphics. The amount of data for both types of graphics is the same, so changing the EGA size to the Tandy size fixes the bug.
As always problem solved,
thanks ripsaw8080 😁
EDIT:
Wrote a patch for it, just copy into the game directory and run it once.
Source included.
