mogul@su-navajo.arpa (Jeff Mogul) (11/23/85)
Since I don't read Unix-wizards, I didn't realize that this had turned into a hot issue; thanks to some other Stanford people for alerting me. I wrote a lot of the "Stanford Unix Pup" software that Xerox has been distributing. We expect to distribute this as "user-contributed" (i.e., totally unsupported) software in 4.3BSD. The CMU/Stanford "packet-filter" device driver will also be in 4.3BSD, probably as part of the official kernel. Please do not ask me (or anyone else from Stanford) for copies of this code; you won't get it from me. Pup is an obsolete protocol, but in much the same way that FORTRAN is an obsolete language ... people still use it. The Stanford Pup system includes Telnet, FTP, Leaf (remote file random access from your Xerox Lisp Machine) and other Pup services (name lookup, gateway-on-a-Vax, etc.) We support both 3Mb and 10Mb ethernets, but no other data link layers. This has been running for several years without any changes, so it is fairly solid. Anyway, we don't intend to do any further work on it. The "Pup" code in the 4.2BSD kernel is bogus; we don't use it at all and I hope it won't be in 4.3BSD. All our code runs in user-mode programs, except for the packet-filter driver (which is not specific to Pup.) I should clear up some misinformation: Pup cannot deal with >255 hosts on a single cable; but Pup is an internetwork protocol (one of the first: see Boggs, Schoch, Taft, and Metcalfe "Pup: an Internetwork Architecture" in IEEE Trans. on Comm., April 1980) so you can have up to 254*255 hosts. Xerox has far more than 255 Pup hosts; I think they have about 125 Pup subnets and thousands of hosts. Stanford has 36 subnets and almost 600 entries in our Pup host table (although 95% of those hosts no longer rely on Pup.)