21 Jun
2005
21 Jun
'05
5:58 p.m.
>>>> "Tony" == Tony Duell <ard
at p850ug1.demon.co.uk> writes:
>> >>>>
"Tony" == Tony Duell <ard at p850ug1.demon.co.uk> writes:
>>
Tony> I suppose you could include the Pro 325 and 350 (no I/D, F11
Tony> chip) and the Pro 380 (split I/D, J11 chip). But those will not
Tony> run normal PDP11 software, the I/O is totally different I
Tony> believe.
> It certainly is -- different and very badly
conceived. But then
> again, Unibus and Q-bus are also different (though not by the same
Tony> Unibus and Qbus are actually quite similar, to the extent that
Tony> devices for either bus generally look the same to the software
Tony> (the DL11 and DLV11 serial ports have the same registers, same
Tony> bit allocations, ...
True. Bad analogy. The "CT bus" (what you find in a PRO) is about as
different from Unibus/Qbus as the ISA bus, only uglier yet.
The truly bizarre thing is that there are hints of DMA capability in
the books, but no actual PRO I/O device does DMA -- not even the hard
drive controller or the ethernet card. That's one of the many strikes
against it...
paul