[HECnet] TOPS-10 KS10 Ethernet Monitor

[Johnny Billquist]

On 2015-04-26 22:14, Cory Smelosky wrote:
> On Sun, 26 Apr 2015, Johnny Billquist wrote:
>
>> All true and good points.
>> I'm curious on exactly how a DEUNA/DELUA works in a KS-10. Does anyone
>> know? Does it do 8-bit-byte DMA to the 18-bit memory, leaving the top
>> two bits alone. Or does it only work if it do word DMA (would be
>> strange, as the controller itself can send and receive odd byte length
>> ethernet packets).
>>
>> And how does the whole controller actually work in a KS, since the
>> controller expects there to be control structures in memory, which are
>> used to manage the buffers. Those are expected to be 16-bit fields at
>> one address, and an additional 2 bits of address in another word.
>>
>> Is there some potential problem with regards to a PDP-11, which have
>> two parity bits for data, which are used for actual data on a KS? (If
>> I remember right.)
>>
>
> How does the DZ do it?  THAT I know is a supported.

Haha... DZ don't do DMA. :-)
There is a reason it is a very disliked peripherial...

>> In short, this is not trivial, and if it works on a real machine, the
>> emulation needs to reflect that truthfully, or else it will not be so
>> useful. I suspect it should work on a real machine, as hints suggested
>> that it was at least considered.
>>
>
> Could always do "emulation mode" and "real hardware mode".

Definitely doable, but if you go down that path, why even make it 
somewhat similar to a DEUNA/DELUA? Then you might as well provide a 
controller with way more functionality...

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol