Talk:Network Control Program (ARPANET) - Revision history

Larsbrinkhoff: /* What is an NCP implementation? */ Foonly F2.

2025-02-04T19:09:14Z

‎What is an NCP implementation?: Foonly F2.

Jnc: /* What is an NCP implementation? */ I'm too lazy to figure out if other machines had AHHP on thm

2025-02-04T16:37:58Z

‎What is an NCP implementation?: I'm too lazy to figure out if other machines had AHHP on thm

Larsbrinkhoff: /* What is an NCP implementation? */ ITS "ARPA"

2025-02-04T15:30:00Z

‎What is an NCP implementation?: ITS "ARPA"

Larsbrinkhoff: /* What is an NCP implementation? */ Will the real ARPA please stand up?

2025-02-04T13:21:24Z

‎What is an NCP implementation?: Will the real ARPA please stand up?

Jnc: /* What is an NCP implementation? */ Still a lot of mysteries though

2025-02-04T12:27:59Z

‎What is an NCP implementation?: Still a lot of mysteries though

Larsbrinkhoff: /* What is an NCP implementation? */ XSWIT is an NCP implementation.

2025-02-04T05:56:32Z

‎What is an NCP implementation?: XSWIT is an NCP implementation.

Jnc: /* What is an NCP implementation? */ new section

2025-02-03T22:32:21Z

‎What is an NCP implementation?: new section

Jnc: /* Alto NCP? */ Those directories have nothing about the NCP era; questions for Taft

2025-01-07T12:38:29Z

‎Alto NCP?: Those directories have nothing about the NCP era; questions for Taft

Larsbrinkhoff: /* Alto NCP? */ Confimed by Ed Taft: no NCP on the MAXC2 front end.

2025-01-07T06:01:26Z

‎Alto NCP?: Confimed by Ed Taft: no NCP on the MAXC2 front end.

Jnc: /* Alto NCP? */ Nova 1822 interface

2025-01-06T16:49:57Z

‎Alto NCP?: Nova 1822 interface

@@ Line 145: / Line 145: @@
 :::: That IMP seems to have had other S1 project machines on it, including a PDP-10 running WAITS (no idea what model CPU it was).
 :::: Note the CHAOS 104xx addresses; that subnet seems to have had only those 4 machines on it. Subnet 21 seems to be the "NM-crock net". [[User:Jnc|Jnc]] ([[User talk:Jnc|talk]]) 17:37, 4 February 2025 (CET)
 :: I can't figure out what the 'Newman' is. At first I thought it was some kind of memory mapping gear (maybe a shared memory between several machines, the way it was talked about); then I found [https://github.com/pdp11/nswit/blob/master/sail/cbf.ncp/dev29.pal/489 this file] which seems to agree. [https://github.com/pdp11/nswit/blob/master/sail/cbf.ncp/dev3.pal/489 This file] has a mystery, though - an asynchronous serial line to an "IMP data line"?

@@ Line 141: / Line 141: @@
 ::: I think it would be these: https://github.com/ttkzw/hosts.txt/blob/master/pub/hosts/19830119/HOSTS.TXT#L474-L477 [[User:Larsbrinkhoff|Larsbrinkhoff]] ([[User talk:Larsbrinkhoff|talk]]) 14:21, 4 February 2025 (CET)
 :: I can't figure out what the 'Newman' is. At first I thought it was some kind of memory mapping gear (maybe a shared memory between several machines, the way it was talked about); then I found [https://github.com/pdp11/nswit/blob/master/sail/cbf.ncp/dev29.pal/489 this file] which seems to agree. [https://github.com/pdp11/nswit/blob/master/sail/cbf.ncp/dev3.pal/489 This file] has a mystery, though - an asynchronous serial line to an "IMP data line"?
 :: [https://github.com/pdp11/nswit/blob/master/sail/cbf.ncp/conf.pal/491 This] has a lot of other mysteries. [[User:Jnc|Jnc]] ([[User talk:Jnc|talk]]) 13:27, 4 February 2025 (CET)

@@ Line 134: / Line 134: @@
 ::: There's a Chaosnet service called ARPA (also NCP and TCP).  ITS also has it.  A Chaosnet machine calls this service to have make a connection out to ARPANET.  Once connection is established, it acts as a regular byte stream Chaosnet/TCP/NCP connection.  I haven't seen clients, but I assume Lisp machines would use this, and that the S-1 project would have some of those.  So when the code says "ARPA", it can be this service, or the DoD office, or the ARPA network.
 ::: Note that there's also an NCP TELNET client (and server, commented out). [[User:Larsbrinkhoff|Larsbrinkhoff]] ([[User talk:Larsbrinkhoff|talk]]) 14:21, 4 February 2025 (CET)
 :: Oh, this code seems like it might have run on a number of different machines, not all of which had 1822 interfaces - "use hardware IMP interface, not Chaos net". I wonder if on non-1822 machines, the AHHP implementation was ''only'' on the machine with an 1822 interface; if not, somehow (perhaps by the link number) incoming packets must have been de-multiplexed and sent on to the correct machine? (This comment - "chaosnet IMP (as opposed to hardware IMP)" - is amusing.)

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 :: I see; but there is something strange going on, per this comment - "This routine is called from the intsk process to read the rest of an ARPA net packet in from the chaos net." Of course, that could be because this box implemented a CHAOS<->NCP protocol 'gateway'. It also seems to be prepared to forward CHAOS packets over the ARPANET ("is this is for link 227 (octal)?"); but it wouldn't need the AHHP implementation if that's ''all'' it did. ([https://github.com/pdp11/nswit/blob/master/sail/cbf.ncp/caface.pal/490 This] seems to be code for the CHAOS<->NCP protocol gateway.)
 :: Oh, this code seems like it might have run on a number of different machines, not all of which had 1822 interfaces - "use hardware IMP interface, not Chaos net". I wonder if on non-1822 machines, the AHHP implementation was ''only'' on the machine with an 1822 interface; if not, somehow (perhaps by the link number) incoming packets must have been de-multiplexed and sent on to the correct machine? (This comment - "chaosnet IMP (as opposed to hardware IMP)" - is amusing.)
 :: It did seem to have an IMP interface; an LH-DH-11 (but there is a different mystery - an [[LH-DH/11 Local/Distant Host Controller]] was a UNIBUS device, but this machine is claiming to be an -11/23, so a QBUS; it must have had a QBUS/UNIBUS converter - although maybe it was actually an [[MLH-DH/LSI11 Multiple Channel Controller]]). I wonder what its ARPANET address was - have you looked for it in an NCP host table?
 :: I can't figure out what the 'Newman' is. At first I thought it was some kind of memory mapping gear (maybe a shared memory between several machines, the way it was talked about); then I found [https://github.com/pdp11/nswit/blob/master/sail/cbf.ncp/dev29.pal/489 this file] which seems to agree. [https://github.com/pdp11/nswit/blob/master/sail/cbf.ncp/dev3.pal/489 This file] has a mystery, though - an asynchronous serial line to an "IMP data line"?
 :: [https://github.com/pdp11/nswit/blob/master/sail/cbf.ncp/conf.pal/491 This] has a lot of other mysteries. [[User:Jnc|Jnc]] ([[User talk:Jnc|talk]]) 13:27, 4 February 2025 (CET)

← Older revision		Revision as of 12:27, 4 February 2025
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	: Worry not. XSWIT implements the ARPANET Host/Host protocol, and talks 1822 to an IMP. [[User:Larsbrinkhoff\|Larsbrinkhoff]] ([[User talk:Larsbrinkhoff\|talk]]) 06:56, 4 February 2025 (CET)		: Worry not. XSWIT implements the ARPANET Host/Host protocol, and talks 1822 to an IMP. [[User:Larsbrinkhoff\|Larsbrinkhoff]] ([[User talk:Larsbrinkhoff\|talk]]) 06:56, 4 February 2025 (CET)
		+
		+	:: I see; but there is something strange going on, per this comment - "This routine is called from the intsk process to read the rest of an ARPA net packet in from the chaos net." Of course, that could be because this box implemented a CHAOS<->NCP protocol 'gateway'. It also seems to be prepared to forward CHAOS packets over the ARPANET ("is this is for link 227 (octal)?"); but it wouldn't need the AHHP implementation if that's ''all'' it did. ([https://github.com/pdp11/nswit/blob/master/sail/cbf.ncp/caface.pal/490 This] seems to be code for the CHAOS<->NCP protocol gateway.)
		+	:: Oh, this code seems like it might have run on a number of different machines, not all of which had 1822 interfaces - "use hardware IMP interface, not Chaos net". I wonder if on non-1822 machines, the AHHP implementation was ''only'' on the machine with an 1822 interface; if not, somehow (perhaps by the link number) incoming packets must have been de-multiplexed and sent on to the correct machine? (This comment - "chaosnet IMP (as opposed to hardware IMP)" - is amusing.)
		+	:: It did seem to have an IMP interface; an LH-DH-11 (but there is a different mystery - an [[LH-DH/11 Local/Distant Host Controller]] was a UNIBUS device, but this machine is claiming to be an -11/23, so a QBUS; it must have had a QBUS/UNIBUS converter - although maybe it was actually an [[MLH-DH/LSI11 Multiple Channel Controller]]). I wonder what its ARPANET address was - have you looked for it in an NCP host table?
		+	:: I can't figure out what the 'Newman' is. At first I thought it was some kind of memory mapping gear (maybe a shared memory between several machines, the way it was talked about); then I found [https://github.com/pdp11/nswit/blob/master/sail/cbf.ncp/dev29.pal/489 this file] which seems to agree. [https://github.com/pdp11/nswit/blob/master/sail/cbf.ncp/dev3.pal/489 This file] has a mystery, though - an asynchronous serial line to an "IMP data line"?
		+	:: [https://github.com/pdp11/nswit/blob/master/sail/cbf.ncp/conf.pal/491 This] has a lot of other mysteries. [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 13:27, 4 February 2025 (CET)

← Older revision		Revision as of 05:56, 4 February 2025
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	As a rule, a machine ''cannot'' have a working ARPANET NCP ''unless'' it is plugged into an IMP. In part, this is because each end of an NCP connection is ''addressed'' by the IMP number+port. No IMP Port - no NCP. [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 23:32, 3 February 2025 (CET)		As a rule, a machine ''cannot'' have a working ARPANET NCP ''unless'' it is plugged into an IMP. In part, this is because each end of an NCP connection is ''addressed'' by the IMP number+port. No IMP Port - no NCP. [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 23:32, 3 February 2025 (CET)
		+
		+	: Worry not. XSWIT implements the ARPANET Host/Host protocol, and talks 1822 to an IMP. [[User:Larsbrinkhoff\|Larsbrinkhoff]] ([[User talk:Larsbrinkhoff\|talk]]) 06:56, 4 February 2025 (CET)

← Older revision		Revision as of 22:32, 3 February 2025
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	Follow up: ''I corresponded with a current staff member, and told him where the final archival tapes might be, if they still existed. You have won this staff member's prize for "Most interesting request in a long time". Alas, the storage room that they were in was reclaimed by the University several years ago, and no tapes were salvaged. This piece of intellectual history is now only a memory.'' [[User:Larsbrinkhoff\|Larsbrinkhoff]] ([[User talk:Larsbrinkhoff\|talk]]) 09:08, 13 December 2024 (CET)		Follow up: ''I corresponded with a current staff member, and told him where the final archival tapes might be, if they still existed. You have won this staff member's prize for "Most interesting request in a long time". Alas, the storage room that they were in was reclaimed by the University several years ago, and no tapes were salvaged. This piece of intellectual history is now only a memory.'' [[User:Larsbrinkhoff\|Larsbrinkhoff]] ([[User talk:Larsbrinkhoff\|talk]]) 09:08, 13 December 2024 (CET)
		+
		+	== What is an NCP implementation? ==
		+
		+	I ask because I see you've added XSWIT to the list. Is that an actual ARPANET NCP, or what? I ask because in the CHAOS/NCP protocol 'gateway' service at MIT, the protocol implemented on the non-ARPANET-connected host (which was using the CHAOS/NCP protocol 'gateway') was not NCP - just the standard CHAOS virtual stream. The AI Lab dorks tended to call any networking software ''an'' NCP - but that's not 'ARPANET NCP'.
		+
		+	("I am far from thinking that nomenclature is a remedy for every defect in art or science: still I cannot but feel that confusion of terms generally springs from, and always leads to, confusion of ideas." -John Louis Petit, "Architectural Studies in France", 1854)
		+
		+	As a rule, a machine ''cannot'' have a working ARPANET NCP ''unless'' it is plugged into an IMP. In part, this is because each end of an NCP connection is ''addressed'' by the IMP number+port. No IMP Port - no NCP. [[User:Jnc\|Jnc]] ([[User talk:Jnc\|talk]]) 23:32, 3 February 2025 (CET)

@@ Line 84: / Line 84: @@
 ::: https://xeroxparcarchive.computerhistory.org/indigo/portola/.index.html
 ::: [[User:Larsbrinkhoff|Larsbrinkhoff]] ([[User talk:Larsbrinkhoff|talk]]) 07:00, 7 January 2025 (CET)
 == BCC-500 NCP? ==

@@ Line 69: / Line 69: @@
 :: Sure, ask, but as I suggested above, the OS environment on the Alto ("the Alto was a personal workstation, whose operating system was pretty elementary - think MS-DOS on a PC, it was about like that") was such that an NCP for it made no sense. (And I found no code for an Alto NCP in the PARC archive.)
 :: His email did ring an interesting bell for me, though: "MAXC1 had a Nova as the front end" - which we knew, but the context of his statement likely indicates that MAXC1 (which we knew was on the ARPANET, and apparently had an NCP) was likely connected to the ARPANET ''through'' the Nova. This ties in with something else you found:
 ::: HOST PARC-GATEWAY,      1/32,USER,,NOVA-800,[PORTOLA]
@@ Line 74: / Line 79: @@
 :: The remaining mystery is what software ran on the PARC-GATEWAY machine. Did it have an NCP - as seems possible from its inclusion in the 1980 host list (3 years before NCP was turned off), or was it just a PUP router? I did a Web search for "PARC-GATEWAY", but i) it was difficult (in Google's 'exact phrase' search function, the "-" character is an operator, with no way to escape it that I could find; and Google search is case insensitive), and ii) I didn't find anything.
 :: Maybe we should try asking some of the early PARC people? [[User:Jnc|Jnc]] ([[User talk:Jnc|talk]]) 17:49, 6 January 2025 (CET)
 == BCC-500 NCP? ==

@@ Line 62: / Line 62: @@
 :: 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. [[User:Jnc|Jnc]] ([[User talk:Jnc|talk]]) 21:05, 20 October 2021 (CEST)
 : Here's something from Lawrence Stewart:
-: ''I designed the Alto BBN-1822 interface, which was used for connecting to the Bay Area Packet Radio network and also used for PARC-MAXC2.  MAXC1 had a Nova as the front end, about which I know nothing, but MAXC2 used an Alto. Both machines were  40 bit word microcoded machines programmed to be PDP-10s.  Corporate wanted PARC to use SDS but the CSL folks wanted a 10, so they had      to build one. ''
+: ''I designed the Alto BBN-1822 interface, which was used for connecting to the Bay Area Packet Radio network and also used for PARC-MAXC2.  MAXC1 had a Nova as the front end, about which I know nothing, but MAXC2 used an Alto. Both machines were  40 bit word microcoded machines programmed to be PDP-10s.  Corporate wanted PARC to use SDS but the CSL folks wanted a 10, so they had to build one.''
 : ''I only tested my own code up to successful loopback to the local IMP, then Ed took over.''
 : This only says there was an interface, not that there was an NCP.  I'll ask. [[User:Larsbrinkhoff|Larsbrinkhoff]] ([[User talk:Larsbrinkhoff|talk]]) 15:10, 6 January 2025 (CET)
 == BCC-500 NCP? ==