> On Sep 17, 2021, at 8:48 PM, Fritz Mueller via cctalk <cctalk@classiccmp.org>
> wrote:
>
> A fully-populated 18-bit address space on the /34 and /45 is only 128K words,
> which seems like a pretty tight fit for a TCP stack with practically sized
> buffers?
>
> I had always sorta assumed DELUA/DEUNA were only practically useful for TCP
> on extended Unibus machines (/70, /44, /24, etc.) but I could certainly be
> wrong on that assumption!
>
> --FritzM.
Certainly the 22 bit machines are a nicer choice, but various operating systems
supported DECnet on 18 bit machines, which is a similar size problem.
As for buffers, one data point is that the DECNA -- the Pro (CT bus) Ethernet
adapter -- has on-board buffer memory. That memory is fixed at 64 kwords. And
compared to typical buffer allocations in DECnet (for RSTS anyway, the one I
know) that's plenty large enough.
paul
