The A2090 is a full length Zorro II card which contains a SCSI controller and an ST506 (IBM XT MFM) controller. The card does not support autobooting, however there were solutions released which allowed the card to boot, such as the Commodore Autoboot Card or the Combitec AutoBoot Card (A2090b). This card may also have been known by a few other names such as the A2500 Hard Disk controller or the Commodore A2094. The A2094 is was actually a hard disk kit from Commodore, containing the A2090a, 40MB HD, cables, mountings, ROMS and manuals. The card uses the Zilog 80B processor. If you intend to use this card in Zorro III machines, then all drivers and buffers must be loaded into Chip RAM and not Fast RAM.
The Commodore A2090a is really just the A2090 with autobooting ROMs onboard. It uses its own custom booting method and ironically does not use the Commodore RDB standard which most hard drive controllers use. In order to prep and format the drive, a special prepping utility is required. You cannot have partitions larger than 256MB without a patch, and this probably applies to the A2090 also. In order to autoboot, you need at least Kickstart 1.3.
Board# Physical Size Revision Number ----------------------------------------------------------- U50 HI Top centre, below J2 28 pin 315098-01 2090 AB5C U51 LO Top centre, below U50 28 pin 315097-01 2090 D32B U36 Top right 28 pin 390230-09 2090a 2FEF Connector/Jumper Description ------------------------------------------------------------ J0 34pin ST506 Control Connector J1 20pin ST506 Data Cable Connector 1 J2 20pin ST506 Data Cable Connector 2 J4 2pin SCSI LED Connector for A2090 J4 2pin Autoboot ON/OFF for A2090a J5 LED Connector CN1 DB25F SCSI Connector CN2 50pin SCSI Connector ***PLEASE NOTE THAT SOME PARTITIONS MUST HAVE THE FOLLOWING NAMES*** Physical Device | 2 Cylinder Section | Unit | First Partition -----------------+--------------------+------+---------------- 1st ST506 Drive | RES0: | 1 | DH0: 2nd ST506 Drive | RES1: | 2 | DH1: 1st SCSI Drive | RES2: | 3 | DH2: 2nd SCSI Drive | RES3: | 4 | DH3: 3rd SCSI Drive | RES4: | 5 | DH4: 4th SCSI Drive | RES5: | 6 | DH5: xth SCSI Drive | RES(x+1): | (x+2)| DH(x+1):
Thanks to Calum Tsang and Dave Haynie
