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 | | From: | Michael Kukat | | Subject: | Re: SCSI ON A VAX 4000/500 - WHAT DO I NEED? | | Date: | Thu, 30 Dec 2004 17:45:51 +0100 |
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 | Hi !
On Thu, 29 Dec 2004, Ben wrote:
> KZQSA definately works as a CD-ROM controller... I've used it to boot a
> VAX 4000-400 back before I sold the whole lot off. Supported or not, I
> don't see why you couldn't boot a hard disk from the card unless the
> hardware/software specifically prevents it. (but I never tried
> that...)
Sure, CD-ROM and TK50Z and stuff works. It's made for this and supported by the
firmware. It even might be the firmware has no limitations in this place and
can boot from hard disks here. But VMS doesn't support this controller as a
hard disk controller. Pure political stuff. It has "just" 128KB buffer, and is
not so intelligent like MSCP adapters, that's the reason why DEC sold this just
as an interface for CD-ROMs and tapes. I didn't get any information about this
thing, otherwise i would have written a driver for NetBSD for it :) But in my
research i heard about the very bad implementation of this board. IIRC, it was
something with the SCSI bus itself, no so much the controller logic.
Technically, this board might even be better than a simple 5390 based SCSI
controller like in VAXstation 3100s, but for a "real" VAX, this board just
wasn't intended to be a true storage interface.
Politically, it's comparable to the onboard SCSI in the VAXstation 2000. You
could boot off TK50Z very fine. But you never saw some hard disk connected to
this controller. After applying a nice patch to the firmware (can be found
somewhere in the net), you could boot off NetBSD very well from SCSI disks on
this controller. But nevertheless, VMS might not support it as controller for
hard disks.
It's not just a matter of booting... The OS also has something to tell :)
....Michael
--
http://www.unixiron.org/ Home Powered by: (Net|Open|Free)BSD IRIX NonStop-UX
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| | From: | John E. Malmberg | | Subject: | Re: SCSI ON A VAX 4000/500 - WHAT DO I NEED? | | Date: | Thu, 30 Dec 2004 16:03:46 -0500 |
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| [followups set to comp.os.vms]
Michael Kukat wrote:
>
> Sure, CD-ROM and TK50Z and stuff works. It's made for this and supported by the
> firmware. It even might be the firmware has no limitations in this place and
> can boot from hard disks here. But VMS doesn't support this controller as a
> hard disk controller. Pure political stuff. It has "just" 128KB buffer, and is
> not so intelligent like MSCP adapters, that's the reason why DEC sold this just
> as an interface for CD-ROMs and tapes. I didn't get any information about this
> thing, otherwise i would have written a driver for NetBSD for it :) But in my
> research i heard about the very bad implementation of this board. IIRC, it was
> something with the SCSI bus itself, no so much the controller logic.
As the KZQSA is an "ancient" adapter, I do not know the exact reasons
that support is limited to CD-ROMs and Tapes.
It may be that it was never tested on magnetic disks, or that one of the
tests with then supported magnetic disks failed, and there was no way to
make it work.
Tapes and CD-ROMS at the time that the KZQSA was produced could not
operate at the data rate of a magnetic disk, and that might allow them
to work reliably, where a magnetic disk might fail a test at high loading.
The tests that Digital/Compaq/HP does for devices intended for OpenVMS
support are by design intended to be worse than anything that a end user
would likely try. Some of them involve fault injection into the
hardware to verify that no driver undetectable data corruption will occur.
There is nothing in the driver for the KZQSA that prevents using it for
magnetic disks, even though it is not supported.
-John
wb8tyw@qsl.network
Personal Opinion Only
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| | From: | Hoff Hoffman | | Subject: | Re: SCSI ON A VAX 4000/500 - WHAT DO I NEED? | | Date: | Tue, 04 Jan 2005 20:58:23 GMT |
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| In article , "John E. Malmberg" writes:
:[followups set to comp.os.vms]
:Michael Kukat wrote:
:>
:> Sure, CD-ROM and TK50Z and stuff works. It's made for this and supported by the
:> firmware. It even might be the firmware has no limitations in this place and
:> can boot from hard disks here. But VMS doesn't support this controller as a
:> hard disk controller. Pure political stuff. It has "just" 128KB buffer, and is
:> not so intelligent like MSCP adapters, that's the reason why DEC sold this just
:> as an interface for CD-ROMs and tapes. I didn't get any information about this
:> thing, otherwise i would have written a driver for NetBSD for it :) But in my
:> research i heard about the very bad implementation of this board. IIRC, it was
:> something with the SCSI bus itself, no so much the controller logic.
:
:As the KZQSA is an "ancient" adapter, I do not know the exact reasons
:that support is limited to CD-ROMs and Tapes.
:
:It may be that it was never tested on magnetic disks, or that one of the
:tests with then supported magnetic disks failed, and there was no way to
:make it work.
The KZQSA isn't expected to operate reliably with SCSI configuratious
outside those that were explicitly supported. Sometimes it worked,
and sometimes it didn't.
We traditionally don't usually describe why we don't support a particular
unsupported configuration, nor specifically detailing what was wrong
(if we tested it), as that can obviously approach a support statement.
We can also obviously choose not to support a configuration for other
reasons -- though in this particular case, the reason was technical.
While Michael Kukat has apparently had this configuration work within
those configuration(s) tested, I've had the KZQSA lock up on me. (For
better or worse, all ancient SCSI configurations are somewhat unstable.)
The HSD05 or similar is the usual and official solution for SCSI on a
Q-bus configuration, and there are (or once were) various third-party
SCSI Q-bus controllers available. The series of MicroVAX referenced
does have DSSI, so DSSI to SCSI adapters are available.
An alternative fix is to find and replace the VAX 4000 series system
with a MicroVAX or VAXstation series system with native SCSI -- this
might be easier, and it might even be cheaper. (This assumes that the
Q-bus is not being used for an "unusual" Q-bus adapter, of course.)
---------------------------- #include -----------------------------
For additional, please see the OpenVMS FAQ -- www.hp.com/go/openvms/faq
--------------------------- pure personal opinion ---------------------------
Hoff (Stephen) Hoffman OpenVMS Engineering hoff[at]hp.com
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