2 Jan
2024
2 Jan
'24
8:56 p.m.
On Tue, Jan 2, 2024 at 11:51 AM Jonathan Stone via cctalk
<cctalk(a)classiccmp.org> wrote:
On Tuesday, January 2, 2024 at 11:29:36 AM PST, thomasdzubin--- via cctalk
<cctalk(a)classiccmp.org> wrote:
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.
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.