20 Jan
2002
20 Jan
'02
8:57 p.m.
On Jan 19, 22:35, jkunz(a)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