Difference between revisions of "Tymshare Base-Host Protocol"

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[[Image:Tymnet-man1.jpg|thumb|right|Humorous visualization of Tymnet protocol]]
 
[[Image:Tymnet-man1.jpg|thumb|right|Humorous visualization of Tymnet protocol]]
  
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This documents the protocol, as used around 1975, between a PDP-10 host and Varian 620 Tymbase.
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This documents the [[protocol]], as used around 1975-1982, between a [[PDP-10]] [[host]] and Varian 620 TymBAS.  At a low level, the interface consists of [[shared memory]]; one page (512 words) at [[address]] 02000 (octal).  The memory has some [[meta-data]] and [[ring buffer]]s for input and output.  The host and the TymBAS regularly poll this memory for updates.
  
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Messages are transmitted from the PDP-10 as 36-bit words with four octets in bits 0-31.  Bits 32-35 are unused.
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Messages are transmitted from the PDP-10 as 36-bit [[word]]s with four [[octet]]s in bits 0-31.  Bits 32-35 are unused.
  
 
Message types A, B, C, and D are just 4 octets.
 
Message types A, B, C, and D are just 4 octets.
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|}
  
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Type G messages have a variable number of octets.  The message number is 200 (octal) plus the total number of octets in the message, including header.
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Type G messages have a variable number of octets.  The message number is 0200 (octal) plus the number of data octets following the 16-bit [[header]].  The last word is padded out to a 36-bit boundary.
  
 
{| class="wikitable"
 
{| class="wikitable"
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| colspan="4" | Data as per ''n''
 
| colspan="4" | Data as per ''n''
 
|-
 
|-
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| colspan="4" | ...
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| colspan="3" | ...
 +
| Padding
 
|}
 
|}
  
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Messages.  Any number not in this list is illegal.
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Type H messages are for sending or receiving a block of words.
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{| class="wikitable"
 +
| Message number
 +
| Port
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| Word count, high 8 bits
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| Word count, low 8 bits
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|-
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| Address, high 8 bits
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| Address, middle 8 bits
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| Address, low 8 bits
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| Unused
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|}
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 +
 
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Messages.  Any number not in this list is illegal.  Numbers 1-41 were present in 1975.  Numbers 42-61 were added around 1982.
 
{| class="wikitable"
 
{| class="wikitable"
 
| Number
 
| Number
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| Host up and answering with # of ports in port byte, and host # in data byte.
 
| Host up and answering with # of ports in port byte, and host # in data byte.
 
|-
 
|-
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| 200+''n''
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| 42
 +
| A
 +
| CLP
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| Super clock info request.
 +
|-
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| 43
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| F
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| CLR
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| Super clock info.
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|-
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| 44
 +
| H
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| BKO
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| Start block output.
 +
|-
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| 45
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| B
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| BOC
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| Block output complete.
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|-
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| 46
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| H
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| BIN
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| Start block input.
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|-
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| 47
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| D
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| INB
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| Block input done, out of buffer.
 +
|-
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| 50
 +
| D
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| INE
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| Block input done, completed.
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|-
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| 51
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| D
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| INT
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| Block input done, timeout.
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|-
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| 52
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| B
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| IRQ
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| Request block input termination.
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|-
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| 53
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| D
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| IHR
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| Block input done, host request.
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|-
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| 54
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| B
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| ORQ
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| Request block output termination.
 +
|-
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| 55
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| B
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| OHR
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| Block output done, host request.
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|-
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| 56
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| C
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| NEG
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| Block IO port negotiation.
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|-
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| 57
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| B
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| BRK
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| Break character received.
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|-
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| 60
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| C
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| PSR
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| Port status.
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|-
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| 61
 +
| B
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| EAO
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| Enter alt output device mode.
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|-
 +
| 0200+''n''
 
| G
 
| G
 
|
 
|
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This information comes from the SUMEX-AIM monitor file TYMSRV.MAC, written by Michael A. Heathman in 1975.
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This information comes from the [[SUMEX-AIM]] monitor file TYMSRV.MAC, written by Michael A. Heathman in 1975.  Additional updates from the [[SRI-NIC]] version from 1982.
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{{semi-stub}}
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==External links==
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* [http://cap-lore.com/Tymnet/ Tymnet information from Norman Hardy]
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* [https://github.com/TYMCOM-X/169281.tape/blob/61a4c1fcd77c19952506cd141ca9bb9dd0adfd4c/fremontdoc/tbase.doc (FREMONTDOC)TBASE.DOC] - TYMCOM-X documenting the Tymeshare Base-Host Protocol.
  
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[[Category: Networking]]
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[[Category: Network Protocols]]

Latest revision as of 07:26, 10 June 2023

Humorous visualization of Tymnet protocol

This documents the protocol, as used around 1975-1982, between a PDP-10 host and Varian 620 TymBAS. At a low level, the interface consists of shared memory; one page (512 words) at address 02000 (octal). The memory has some meta-data and ring buffers for input and output. The host and the TymBAS regularly poll this memory for updates.

Messages are transmitted from the PDP-10 as 36-bit words with four octets in bits 0-31. Bits 32-35 are unused.

Message types A, B, C, and D are just 4 octets.

Message number Port Subtype or data Data

Type F messages total 8 octets:

Message number Port Data Data
Data Data Unused Unused

Type G messages have a variable number of octets. The message number is 0200 (octal) plus the number of data octets following the 16-bit header. The last word is padded out to a 36-bit boundary.

200+n Port Data Data
Data as per n
... Padding

Type H messages are for sending or receiving a block of words.

Message number Port Word count, high 8 bits Word count, low 8 bits
Address, high 8 bits Address, middle 8 bits Address, low 8 bits Unused


Messages. Any number not in this list is illegal. Numbers 1-41 were present in 1975. Numbers 42-61 were added around 1982.

Number Type Name Comment
1 A ANS System is answering.
2 A SHT System is up but shut.
3 A CRS Sender is crashed.
4 A DIE Recipient should crash.
5 A NSP Base taken over by new supervisor.
6 B LOG Login, next 4 data characters are the info about terminal type, and port or origin, then name, etc.
7 B AUX Supervisor response to establishing auxiliary circuit.
10 B NOP Back pressure on.
11 B OUP Back pressure off.
12 B GOB Character gobbler.
13 B ZAP Circuit zapper.
14 B EDC Enter deferred echo mode.
15 B LDC Leave deferred echo mode.
16 B GRN Green ball.
17 B RED Red ball.
20 B YEL Yellow ball.
21 B ORG Orange ball.
22 B HNG Hang character - not used.
23 B ETM Enter 2741 transparent mode.
24 B LTM Leave 2741 transparent mode.
25 C LOS Lost ball, data has been lost from buffers. The data filed may tell how many were lost.
26 C SUP Supervisor request (aux circuits).
27 C SUR Supervisor response (aux circuits).
30 C AXC Supervisor string character.
31 F TSP Test pattern probe.
32 F TSR Test pattern response.
33 F SAD Host sad.
34 B ECN Echo on.
35 B ECF Echo off.
36 D TCS Term characteristics, first data byte indicates which characteristics second data byte indicates value to set to.
37 C TCP Term characteristics probe, data byte indicates which terminal characteristic were requested.
40 D TCR Term characteristics response, data is just like TCS, comes in response to a probe; also is reflected by remote when terminal characteristics are sent.
41 C HSI Host up and answering with # of ports in port byte, and host # in data byte.
42 A CLP Super clock info request.
43 F CLR Super clock info.
44 H BKO Start block output.
45 B BOC Block output complete.
46 H BIN Start block input.
47 D INB Block input done, out of buffer.
50 D INE Block input done, completed.
51 D INT Block input done, timeout.
52 B IRQ Request block input termination.
53 D IHR Block input done, host request.
54 B ORQ Request block output termination.
55 B OHR Block output done, host request.
56 C NEG Block IO port negotiation.
57 B BRK Break character received.
60 C PSR Port status.
61 B EAO Enter alt output device mode.
0200+n G Data.

This information comes from the SUMEX-AIM monitor file TYMSRV.MAC, written by Michael A. Heathman in 1975. Additional updates from the SRI-NIC version from 1982.

External links

Retrieved from "https://gunkies.org/w/index.php?title=Tymshare_Base-Host_Protocol&oldid=29967"