Commodore, USA
A2000, A3000, A4000
Zorro II
Autoconfig ID
514 / 2,3,10
    SCSI controller
  • Western Digital 33C93
  • uses the same DMAC custom chip for DMA transfers as the A3000
  • knows the Rigid Disk Block and SCSI Direct protocols
  • built in XT IDE (8 bit) hard disk controller - the connectors and LED are not installed but their place is visible on the card
  • 50 pin internal SCSI header
  • DB25 external connector
  • a 3.5" hard disk can be mounted on the card
  • 16 kB autoboot ROM (can be disabled) - autobooting requires at least Kickstart 1.3
    • revision 7.0 of the ROM is necessary for 68040 machines
  • supports SCSI network sharing
  • supported by Linux, NetBSD and OpenBSD
  • A-Max II driver (scsi.amhd)
  • sixteen DIP sockets accept 0.5, 1 or 2 MB RAM
  • supports 256k×4 (44256) chips, 120 ns or faster
  • cannot use DMA to transfer data to 32 bit fast RAM
  • if Zorro II DMA memory is not available the driver falls back to programmed I/O transfers
  • performs extremely slow in the A4000 because of the above mentioned two problems
Commodore A2091 -  front side
front side
Commodore A2091 -  back side
back side