On Tue, Jan 2, 2024 at 11:51 AM Jonathan Stone via cctalk <[email protected]> wrote: > > On Tuesday, January 2, 2024 at 11:29:36 AM PST, thomasdzubin--- via cctalk > <[email protected]> wrote: > > > Can I install the KFQSA card in my 4000-200, disconnect the internal disks > > from the SHAC and connect the disks to the KFQSA thereby allowing NetBSD > > >to run? > > Oh wait, your "Vax 4000-200" is a KA660 in a BA215? Then the internal DSSI is > connected via the 50-pin connector piggybacked on the KA660. > Not via the BA430 backplane. Connecting the KFQSA's external DSSI connector > to the other end of the DSSI bus, via an external DSSI cable, should still > work. > > The possible problem with just disconnecting the DSSi internal cable from the > CPU and leaving it hanging, is no longer terminating that end of the DSSI bus. >
The BA215 internal DSSI cable wouldn't be left hanging when it is disconnected from the KA660 DSSI connector, it would be connected to the KFQSA instead. So there would be no DSSI bus termination issues. I have a BA215 that I sometimes alternate between a KA660, and an M7554 KDJ11-D/S PDP-11/53 (which was originally a DECserver 550 CPU board). When the M7554 KDJ11-D/S is installed I either use a QBus SCSI controller, or a KFQSA attached to the internal DSSI bus.
