16 Feb
2015
16 Feb
'15
1:28 a.m.
Need more experience finding Waldo, too! I see that only C/D have the
MKA11 in their associated-rack, so that's 1 Mw/CPU in the configuration
seen.
What's going on in the A/B associated racks? I see what appear to be three
BA11-L chassis (lower-A; upper- & lower-B). And then a non-standard
forward-facing vertical-orientation quad-height(?) module-cage in mid-B
(any ideas as to what that might be; the bit of backplane visible to the
left looks more like something QBus-era)? Finally there's the large blank
cover in upper-A ...
What role might the 11/44(?) have played (really fancy serial-console)?
Looks rather aged in appearance; surprising.
Would those have been MASSBUS drives in that 4-wide rack-set (perhaps
hidden behind the lower panels; not sure about the row immediately above
that, but the two to the upper-right appear to be RL02)?
On Mon, Feb 16, 2015 at 3:23 AM, Paul Birkel <pbirkel at gmail.com> wrote:
Ah. I need to count better. There are *two* MKA11
per CPU, thus each
only *needs* just a 1 Mw configuration due to address-space limitations.
On Mon, Feb 16, 2015 at 3:05 AM, Paul Birkel <pbirkel at gmail.com> wrote:
Notice the two unused connectors on the M8162
there in the middle slot
(#15).
As this looks like an operational configuration, I infer that those two
connectors are used for ... nothing? Test points (through series
resistors)?
I see (how can one miss!) the address and data ribbon-cables. The
remaining white ribbon-cables must be for the box controllers. So, that
looks like a 1Mw configuration. Maybe 1.5Mw if, as you suggest, you're
careful?
Agree about the missing documentation :-<.
Thanks for the better pic-pointer; knew that I can seen those in the past
but couldn't recall where (and Google didn't help).
On Sun, Feb 15, 2015 at 8:56 PM, Eric Smith <spacewar at gmail.com> wrote:
It appears that the module utilization of the
MKA11 is significantly
different than the MK11, so it must have a much different backplane.
The photo of the MKA11 only shows eight storage array modules, in
slots 9-12 and 18-21, though slots 5-8 and 22-25 might also be
available for storage array modules. The memory bus cabling is
obviously quite cumbersome, and adding storage modules in slots 22-25
looks like it could exacerbate that problem.The MK11 supports 16
storage array modules in slots 2-9 and 18-25. The module assignments
for the non-storage modules also appear to be different.
It's a shame that the KB11-Cm and MKA11 field maintenance print sets
aren't anywhere to be found. While the available 11/74 documentation
offers a description of how the KB11-Cm differs from the KB11-C
(mostly interlocked ASRB and cache bypass), it's a shame that we can't
study the actual details of how those changes were implemented.