From mboxrd@z Thu Jan  1 00:00:00 1970
From: pete@dunnington.u-net.com (Pete Turnbull)
Date: Sun, 20 Jan 2002 14:57:31 GMT
Subject: [pups] 2.11BSD disklabel-programm
In-Reply-To: jkunz@unixag-kl.fh-kl.de
        "Re: [pups] 2.11BSD disklabel-programm" (Jan 19, 22:35)
References: <200201192135.g0JLZ0N01772@unixag-kl.fh-kl.de>
Message-ID: <10201201457.ZM10594@mindy.dunnington.u-net.com>

On Jan 19, 22:35, jkunz at unixag-kl.fh-kl.de wrote:

> Only the first 3 slots are Q/CD. The other 5 slots are Q/Q in serpentine
> bus grant wiring. Tony said that the memory should be in the first
> slot.

Lothar later said this is an H9276-A.  That's a straight backplane, all
Q22/CD.  It seems he has a BA11-S not a BA23 :-)

BTW, DEC normally recommended all comms and network cards go after the
memory, tapes next, then disks.

> AFAIK some 11/73 labeld boxen where sold with a 11/83 CPU in the first
> slot and the memory in the second.

It's the order of the boards (and the boot ROMs) that make it 11/73 or
11/83, not the circuit board.  Though original 11/73s are 15MHz and
original 11/83s are 18MHz.

> AFAIK a 11/83 CPU can use QBus and (or?) PMI memory. If it is
> configured with QBus memory it is calld a "11/73". But keep in mind
> that there is a "real" 11/73 CPU (M8192 = KDJ11-A).

That's a dual-height board, CPU only, with no boot ROMs, LTC, or SLUs.  It
was only sold as an OEM product or as an upgrade to 11/03 or 11/23 (not
11/23+ or microPDP-11/23) systems.  Whilst it is a "real 11/73", it's no
more "real" than any other :-)

> Hmm. Are there Q/CD only BA23 backplanes?

No.  There are straight Q/CD and serpentine Q/Q backplanes of the same size
but they're only used in other boxes (like BA11-N and BA11-S) or sold as
OEM units.

> I never saw a front panel like that, but your assumption sounds right.
> All my front panels have only one disk write protect / online switch.

The BA23 was only rated for one hard disk and either a TK50 or an RX50, but
the BA123 (which uses the same panels) was rated for up to 4 MSCP devices.
 That's why the WP and ONLINE switches and LEDs are on a subassembly, so
you can add another one.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York