MAMEWorld Forums - EmuChat - Re: skyarmy and rom FIXED BITS curiosity

>It's just a helpful diagnostic produced by MAME's romcmp tool, which can only catch a few
>types of common dumping errors. Depending on the hardware, some romcmp errors might not
>even be errors: oversize ROMs are common and graphics ROMs and bipolar decoding PROMs might
>not need all the data outputs that the part has.

>A few types of dumping errors romcmp can't detect but have occurred:

One or two bad bits (as in Sky Army).
Fixed bits that extend only through certain areas of the dump. (I've patched a few cases of this by hand.)
Bridges between address lines that cause 3/4 mirroring (as happened with the Eeekk! color PROM).
Faulty internal latches on 8048, 8041 or related MCUs.

Good example(s) that I overlooked. I always went the first entry. That was first one that would come to mind.

>The "FIXED BITS" message is not at all mandatory.

I had thought it was some protocol procedure, but somewhat rarely used. The last one I recall was Midway's Road Runner with one rom data file getting //fixed bits comment until Guru found another Midway Road Runner pcb and dumped rom from that pcb and replaced rom that was already in MAME source that was used with Midway Road Runner. That had to have been over 10 years earlier iirc.

During the years when Nicola Salmoria was overseeing the project some of the early mandates included no support for gambling type video games until Aaron relaxed that back in 2006. One of the other mandates by Nicola was having specific bootleg coinop videogames removed from support in MAME. Bootleg video coinop games in which the only difference between original versus bootleg was graphics hacks had to be removed from MAME back in 2001 or maybe it was 2002. That decision also created a small bit of dismay back then. I believe that decision was also relaxed by Aaron when Aaron was in charge in 2006.

You missed out on all the emudrama back in the early days on old MAME.net web site and forum days in which Gridle / Santeri S. had to beat down some of the posters and complaints on old MAME.net forums.

On occasion PacDude was over the top where one time Aaron had a complex coinop game finally emulated and he might post about it on old MAME.net forum. PacDude's reply to Aaron might have been: 'now go emulate Slither dammit'.