VAX & PDP-11 Stuff To Clean Out

Glen Slick glen.slick at
Thu Nov 7 22:54:06 CST 2019

On Thu, Nov 7, 2019 at 6:36 PM Jules Richardson via cctech
<cctech at> wrote:
> On 11/6/19 12:16 PM, David Coolbear via cctech wrote:
> > M5976-AA KZQSA SCSI Controller Q
> Hmm, I could sure use one of those...
> I bought a bunch of QBus boards from my recycler quite some time ago, but
> the systems that they'd been pulled from were run with SMD drives. Finding
> a working SMD drive is something of a challenge, but SCSI at least opens up
> possibilities of emulated storage (or real spinning rust, I may still have
> a suitable drive or two, albeit currently on the other side of the Atlantic)

An M5976 KZQSA is not an MSCP compatible controller. If I remember
correctly an M7626 KA660 VAX 4000-200 or better CPU is necessary to
boot from it, and the only OS that supports it is VMS, and only SCSI
CD-ROM drives are officially supported.

I have never tried to boot VMS from a SCSI hard drive attached to an
M5976 KZQSA, or tried to access a SCSI hard drive attached to an M5976
KZQSA after booting VMS from a different drive. I have only used them
for installing VMS from a CD-ROM on a VAX 4000, or for installing
layered products from a CD-ROM on any Q-Bus VAX after VMS is already
installed. For that limited purpose they work well.

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