Initially i built the 68000 Cromix system using high density 5.25″ disk drives for the system drives. Having been able to install Cromix it was time to take the next step and add genuine 8″ drives.
The selected drives were Mitsubishi M2896-63 half height drives.
The 16FDC disk controller was designed primarily for Cromemco Persci drives. I don’t have of these drives and am unlikely to ever find any.
The 50 pin interface is quite different. I stumbled on this document by Martin Eberhard that examined in detail how to adapt the 16FDC to use Shugart SA800/850 drives.
I shamelessly used this very handy information to make an adapter cable for the Mitsubishi drives.
| 16FDC Pin | 16FDC Signal | Drive Pin | Drive Signal |
| 2 | Side_Select | 14 | Side_Select |
| 4 | DS4_L | 32 | DS4_L |
| 6 | N/C | 6 | Alternate I/O |
| 8 | N/C | 8 | Alternate I/O |
| 10 | Seek_Complete_L | ||
| 12 | Restore_L | ||
| 14 | Eject_L | ||
| 16 | N/C | 16 | Alternate I/O |
| 18 | DS3_L | 30 | DS3_L |
| 20 | Index_L | 20 | Index_L |
| 22 | Ready_L | 22 | Ready_L |
| 24 | Motor_On_L | 18 | Alternate I/O /Head_Load_L / Motor_Start_L |
| 26 | DS1_L | 26 | DS1_L |
| 28 | DS2_L | 28 | DS2_L |
| 30 | N/C | ||
| 32 | N/C | ||
| 34 | DirC | 34 | Select (Direction) |
| 36 | Step_L | 36 | Step_L |
| 38 | Write_Data_L | 38 | Write_Data_L |
| 40 | Write_Gate_L | 40 | Write_Gate_L |
| 42 | Track_0_L | 42 | Track_0_L |
| 44 | Write_Prot_L | 44 | Write_Prot_L |
| 46 | Read_Data_L | 46 | Read_Data_L |
| 48 | N/C | 48 | Not Used |
| 50 | N/C | 50 | Not Used |
| 2 | Alternate I/O / Write Current Switch | ||
| 4 | Alternate I/O | ||
| 10 | Alternate I/O | ||
| 12 | Alternate I/O | ||
| 24 | Not Used |
[Next time a drive is out, get the jumper settings.]
I reinstalled Cromix 20.09 on the 8″ disks using the same instructions as i had used previously.