30 Jun
2010
30 Jun
'10
2:56 p.m.
On 6/30/2010 10:23 AM, Eric Smith wrote:
I believe s/w could have examined PSW<8> the 'CIS Instruction Suspended'
bit in the KB11-E w/o the CIS option installed, and it could have set
that bit to a one, whereas in the 11/70 that bit would have been locked
at zero.
Correct. The only backplane that could accept the KE74-A CIS option was
the '11/74' KB11-E backplane.
Johnny Billquist wrote:
Correct. 11/74 was the KB11-E. 11/45 was the KB11-A, 11/55 was the
KB11-D, just to complete the table.
Another way to name them would perhaps be:
KB11-B - Old 11/70 CPU with synch FPP.
KB11-C - New 11/70 CPU with asynch FPP.
KB11-CM - MP modified KB11-C
KB11-E(?) - The new 11/74 CPU with asynch FPP and CIS.
I seem to remember reading somewhere that the 11/74 CPU were to be
called KB11-E, but I also have this nagging feeling that KB11-E might
have been the 11/44, or possibly the 11/60.
The 11/44 CPU was a KD11-Z. The 11/60 CPU was a KD11-K. Now, as I myself pointed out, RSX regards the
11/70mP as an 11/74,
and that is also what the CPU identification code in RSX calls it.
Since the 11/70mp and 11/74 were never official products, there was a
lot of conflation of the designations. Without the optional CIS,
software can't easily distinguish an 11/70mp from an 11/74, so it
probably simply didn't bother to try. Thus whether software reports
the CPU as an 11/70mp or an 11/74 doesn't really prove much of anything. But if we call this an 11/74, what shall we call
the 11/70 with CIS?
Fantasy? There wasn't such a thing, since there wasn't an 11/70 with
a KB11-E CPU that was necessary to accomodate the KE74-A CIS.
Eric