Retro networking / WAN communities

[Paul Koning]

> On Apr 11, 2022, at 8:16 PM, Cameron Kaiser via cctalk <cctalk at classiccmp.org> wrote:
> 
>>>> I still have 10 Mb Ethernet at home (on my Pro, and while it's not in use I have a few 10Base2 bits).
>>> Please expand "my Pro".  There's not much to go on. #LivingRetroVicariouslyThoughOthers
>> DEC Professional 380 (and a caseless 350) -- PDP-11s with a screwball bus and their own set of peripherals.  I have an Ethernet card for one of them.  Working on the driver.
> 
> I'd love Ethernet to work in Venix/PRO but I think my 380 is just going to have
> to do some user-level SLIP driver. I suppose that's something I could write up
> for gits and shiggles.

Perhaps you could adapt the Linux or NetBSD driver for the 82586.  I'm not sure the NetBSD one is complete but the Linux one (sun3-82586.c) looks plausible.  You'll also need to study the CNA chapter of the Pro technical manual (on Bitsavers) since the board includes some additional control logic as well as the packet memory that the chip talks to.  And of course, you'll get to discover all over again that Intel never could design Ethernet chips for beans; the 586 is an especially ugly example of architural absurdity, with its linked list of descriptors that introduce lots of bad race conditions between the CPU and I/O device.  (The depressing thing is that Dijkstra figured out and documented how to do this right 20 years earlier.)

	paul