Wiki editing discussion

As we know that the VRAM and the VDP are also used by the Sega part, maybe it's an Engine that controls the use of VDP and VRAM by the MSX1 or Sega part.

How do you "know" that?
The MD PCB on that photos is fully populated with the RAM for the 68k, the Z80 and the VDP.
Besides, it would be quite an achievement to use DRAM on the MD, since there's no refresh circuitry and the MD VDP uses dual ported VRAM.

@gdx: for info about UM6561BF, look here: https://forums.nesdev.org/viewtopic.php?t=15342 - I guess the "B" maybe corresponds to a revision.

Interesting this precision:

Suffix info :
UM6561F-1 - NTSC
UM6561F-2 - PAL-B
UM6561F-3 - PAL-M
UM6561F-4 - PAL-N

Is the 3rd slot of AX-990 used in a similar way to this PCB: https://www.gadunky.com/product/megadrive-genesis_cartridge_... ?

The description precises that "This is a printed circuit board (PCB) for non battery save Sega Mega Drive/Genesis games. If your game has a broken board, or you want to play a ROM hack on actual hardware, this is for you."

Tested ML-30FD with 2 drives (set to DS2 and DS3) on ML-G30. The drives are not recognised so there is no support in the ROM for 4 drives. The manual mentions support for 5" (a common way to describe what we know as 5.25") drives. The only way they would work is if the internal drives are disconnected. Formatting will probably only be possible on 80 track so called 4DD drives, but reading disks should work (I will try if I can find some external drive unit probably for Fujitsu FM-7 as they use the standard Shugart connector).