Amiga Storage Peripherals

Commodore A2091

> Company: Commodore, USA
Date: 1991
Amiga: 2000, 3000, 4000
Interface: Zorro 2
Autoconfig ID: 514/1,3,10

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


Amiga Commodore A2091

Front: Amiga Commodore A2091