Mame experts : why are some Sega boards so difficult to emulate?

[Larry Philips]

Hi,

 

I got a question for Mame experts.

I noticed that roms for some Sega boards (Model 2, Model 3, Naomi etc.) don't seem to work under Mame, even the latest version.

Quite surprising to say the least, as 

- these systems work with other dedicated emulators (Model 2 Emulator, Supermodel...)

- Naomi and Dreamcast are very similar, and Dreamcast emulation is quite good nowadays

- same generation systems by Capcom, Namco... seem fairly well supported under Mame

 

Mame developers are very good and do a fantastic job so I was wondering, on a purely technical level, what makes some Sega boards so difficult to emulate?

Any idea?

 

Thanks

[PlayStation 2]

Could just be a lack of proper implementation of certain arcade boards. Model 2, Model 3 and NAOMI more than likely aren't nearly as well-studied in the context of MAME to the extent that something like the CPS2 or the Namco System 22.