[cctalk] Re: VAX 4000-200 in BA215 chassis. Can I install a KFQSA card and connect the cabinet disks to it?
On Tue, Jan 2, 2024 at 11:51 AM Jonathan Stone via cctalk wrote: > > On Tuesday, January 2, 2024 at 11:29:36 AM PST, thomasdzubin--- via cctalk > 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.
[cctalk] Re: VAX 4000-200 in BA215 chassis. Can I install a KFQSA card and connect the cabinet disks to it?
When you get it working maybe post some pictures or a brief description of the setup. I have a 4000-700 that I believe was used in some sort of dual mode like you describe, but it's still on my to be explored list On Tue, Jan 2, 2024, 2:51 PM Jonathan Stone via cctalk < cctalk@classiccmp.org> wrote: > > On Tuesday, January 2, 2024 at 11:29:36 AM PST, thomasdzubin--- via cctalk > 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. >
[cctalk] Re: VAX 4000-200 in BA215 chassis. Can I install a KFQSA card and connect the cabinet disks to it?
On Tuesday, January 2, 2024 at 11:29:36 AM PST, thomasdzubin--- via cctalk 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.
[cctalk] Re: VAX 4000-200 in BA215 chassis. Can I install a KFQSA card and connect the cabinet disks to it?
On Tuesday, January 2, 2024 at 11:29:36 AM PST, thomasdzubin--- via cctalk 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? Ive read (here?) that he BA430 has special magic which connects the KA660's SHAC to the internal DSSI bus, via the Q22 fingers. The KA660 ROM has built-in machinery to configure DSSI, both the onboard SHAC and a KFQSA. So in theory, you could use the KA660 boot-rom to configure the KFQSA.to a different DSSI node number (not already in use). Connect the KFQSA to the "end" of the internal DSSI bus, via the DSSI bulkhead. NetBSD won't recognise the SHAC, so you shouldn't need to disconnect the internal DSSI bus, at least for manually booting from the KFQSA rather than the SHAC. I have not yet tried this myself, though -- my BA430 has a KN220.
