Talk:Network Control Program (ARPANET)
Preserved implementations
Multics and TOPS-20 (and I think maybe TOPS-10 too) have been preserved, and run under emulators, but I don't know if their NCP's were included in what was preserved. Jnc (talk) 13:53, 15 October 2021 (CEST)
- Yes, TOPS-10 is also alive and well. Many versions too: at least some of 5.x, 6.x, and 7.x. Larsbrinkhoff (talk) 15:06, 15 October 2021 (CEST)
POSIX/Linux version
You're officially insane! :-) Jnc (talk) 14:40, 18 October 2021 (CEST)
- I actually wanted to make a small ARPANET using the SIMH IMP emulator, with some historical hosts like ITS and WAITS. But to do that I first need to have a good debug tool, so might as well make it an NCP suite. It remains to be seen how far it can go. Larsbrinkhoff (talk) 15:18, 18 October 2021 (CEST)
MOS NCP?
I'm pretty sure there wasn't one. Both the TIU and PE had Host-to-IMP Protocol implementations, of course, but that's only the bottom layer of a complete NCP stack, which also included the ICP and AHHP. Jnc (talk) 15:54, 19 October 2021 (CEST)
- Given your feedback, I'll remove it. I still wonder how come may hosts were listed as "MOS" in the 1982 hosts lists: https://github.com/ttkzw/hosts.txt/blob/master/pub/hosts/1982/host_names_1982_part_1.pdf etc. Larsbrinkhoff (talk) 16:01, 19 October 2021 (CEST)
Those seem to be either Port Expanders (which were so popular that it became a product for SRI - see here), or possibly TIUs in 'milking machine' mode (a Dave Clark term for using a TIU to put a time-sharing system without TCP on the Internet), or BBN gateways (routers - like I said, BBN switched from originally running ELF in its gateways to MOS, and it had apparently happened by the date of this list). Looking at the 'MOS' entries in part1 (only - with no copy/paste, re-typing got tiresome):
- ARPA-DMS - says "LSI-11/03 (MOSS) [sic-JNC] -> HP-3000(MPE-IV)" - TIU fronting the HP?
- BBN-GATEWAY - "PDP-11/40 (MOS) -> SATNET" - probably ran ELF originally, so an -11/40
- BRAGG-GWY1 - "LSI-11/02 [sic-JNC] (MOS)" - likely a Packet Radio router
- CENTACS-MMP - "PDP-11/34 (MOS) -> 7 CDC-5600s(MPX-RT)" - likely a PE, in front of all those other machines
- CENTACS-TF - "PDP-11/34 (MOS) -> various machines" - ditto
I just never heard of anything running under MOS that would have needed/used an NCP. All the things I ever heard of were either on IP (various router projects) or TCP (TIU). Jnc (talk) 17:30, 19 October 2021 (CEST)
Alto NCP?
Although it's true that there was an Alto 1822 interface (something that was unknown to me until I read that email), I'm not sure there was ever an Alto speaking NCP on the ARPANET - that email says the interface "was used to connect to the Bay Area Packet Radio Network and for connecting PARC-MAXC2 to the Arpanet". Amusingly, The Maxc Systems, by Edward R. Fiala (thanks deeply for finding that, and putting in online, BTW - an incredible historical resource, which has saved an almost-forgotten chapter of history) says "Maxc2 is not connected to the ARPA network"!) MAXC2 did use an Alto as its front end, but I wouldn't count that as 'an Alto on the ARPANET'.
I poked around in the Alto 1822 code a bit, and although PupAlImp.decl does contain this line:
maxLinkNCP = 71 // Highest NCP link
most of it seems to be concerned with sending either IP or PUP packets over the ARPANET. (I recall the attempt to send PUP packets to PARC from MIT over the ARPANET; it was a colossal failure, as the MIT PUP address space used MIT subnet numbers, and thus overlaid the PARC PUP address space.)
It makes sense that there wasn't an Alto 'on the ARPANET' (i.e. speaking NCP), as the Alto was a personal workstation, whose operating system was pretty elementary - think MS-DOS on a PC, it was about like that. So it wouldn't make sense to put one of them on a rare (and expensive) IMP port. To confirm, I went to HOSTS.TXT, and:
- I couldn't find MAXC2 in any of them (!) - unexpected, and somewhat un-related to the point of the examination - maybe it was only on for a short period, given the email above
- The only hosts shown on IMP 32 (the Xerox IMP), other than MAXC, are:
HOST : 10.2.0.32 : PARC-GW : ALTO : ALTO-OS :: HOST : 10.3.0.32 : KESTREL,SCI-ICS,SCI,KES,SCT : FOONLY-F3 : TENEX : TCP/TELNET,TCP/FTP,TCP/SMTP :
but i) by this point in time, NCP had been tuned off (19830728-HOSTS.TXT is the last one with NCP hosts listed), ii) the Alto is clearly a gateway (router).
Interestingly, re MOS, in 19830527-HOSTS.TXT, I did see:
HOST : 10.0.0.28 : ARPA-DMS : LSI-11/3 : MOS : NCP/TELNET :
but I suspect that's a typo; it was almost certainly a TIU. (I couldn't find anything about ARPA-DMS in a Web search.) Jnc (talk) 18:16, 20 October 2021 (CEST)
