The
sii driver provides support for the DEC SII SCSI adaptor ASIC used in the DECstation 2100, 3100, and 5100, and in the VAXstation 3100.
The
sii is a medium-performance implementation of the SCSI-I common command set supporting synchronous and asynchronous SCSI devices.
The SII cabling is unusual: the bulkhead connector is very similar to a standard submicro wide SCSI-II connector, but has the other gender.
The
sii chip only supports DMA to or from a fixed window in memory. The driver uses this "window" area as a bounce buffer, copying data to and from the DMA region.