SII(4)

NAME
sii - SII SCSI adaptor

SYNOPSIS
sii0 at mainbus

DESCRIPTION
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 asychronous 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.

SEE ALSO
intro(4), rz(4), tz(4), sd(4), st(4), cd(4), ch(4).

HISTORY
The sii driver first appeared in 4.4BSD.

BUGS
The sii driver only supports the oldscsibus higher-level layer, and the rz and tz devices, which first appeared in 4.4BSD /pmax. It should be re-written to support the scsibus machine-independent higher-level SCSI layer and the sd, st, and cd drivers. This is