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)

Ah, makes sense. Jnc (talk) 15:20, 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)

But then Al said a friend of his was making a simulated ARPANET with Alto(s?).

Which 'Al' is this? Kossow? If you could get some more info from him about what he's planning, that would be good. Note that it might not be an Alto with NCP; there was an Alto IP router connected to the ARPANET - maybe he was planning on using those? (Oh, BTW, look at LoadImpFrontEnd.cm; it loads a whole bunch of PUP modules, but I don't see anything NCP-ish).

Also, if you're looking for ARPANET nodes, I could upload the TIU code. No NCP, but it would generate ARPANET traffic. The MIT V6 would have to be brought up (unless you've got MACRO-11 running somewhere else), to build loads, and SIMH would have to be updated to support the SRI 1822 interface, but it should be doable without too much work. I found the manual for the SRI interface online (at NTIC, IIRC); I should do a CHWiki page for it. Jnc (talk) 21:05, 20 October 2021 (CEST)

This is from a 1980 SYSENG; HOSTS >

HOST PARC-GATEWAY, 1/32,USER,,NOVA-800,[PORTOLA]

HOST PARC-MAXC, 0/32,SERVER,TENEX,PDP10,[PARC,MAXC,MAXC1,XEROX-PARC]

HOST PARC-MAXC2, 2/32,SERVER,TENEX,PDP10,[MAXC2]

Larsbrinkhoff (talk) 19:12, 20 October 2021 (CEST)

Ah, good; I thought I recalled seeing it in a host table at one point, back then. Interesting; it was plugged into port 2 on the Xerox IMP; 'PARC-GW' got plugged in there later - but port 1, 'PARC-GATEWAY' here, seems to have gone unused. Odd. Jnc (talk) 21:05, 20 October 2021 (CEST)

BCC-500 NCP?

Seems I better bring up new entries up here for discussion first.

Al also says he's got the BCC-500 operating system including NCP. But it's unclear if the HP-2100 front end code interfacing with the IMP is there. Larsbrinkhoff (talk) 19:14, 20 October 2021 (CEST)

After the hassle over the 'Alto' NCP (which I am almost certain did not exist), along with the MOS and MINITS cases (ditto), I would in general prefer to have good evidence freely available (i.e. the BCC-500 operating system online, which it doesn't seem to be at either of the two locations in BCC 500), but in this particular case I can make an exception since I'm pretty sure the machine was online in Hawaii. Jnc (talk) 17:20, 25 October 2021 (CEST)

Yes, a good reference (source code or article) might be a criterion. Something like a Wikipedia <ref> would be nice.

PDP-11 NCP users

Quite a few sites (including BBN, IIRC) used the UIll NCP; this mail log gives a sense of the fix/update distribution (using the ARPANET, naturally :-). To compile a complete list, one would only have to look at the host table. It was apparently used with V7 as well as V6. (I have this vague memory that the work first started under V5?) Jnc (talk) 12:30, 29 June 2022 (CEST)