Digital Data Communications Message Protocol - Revision history

Vaxorcist: /* Synchronous DDCMP Controller Capabilities */ Correction: No DDCMP support for DPV11 in VMS

2025-10-16T08:01:22Z

Synchronous DDCMP Controller Capabilities: Correction: No DDCMP support for DPV11 in VMS

← Older revision		Revision as of 08:01, 16 October 2025
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	\| VAXBI \|\| [[DSB32]] \|\| colspan="2" \| X (supported DDCMP versions yet unknown) \|\| - \|\| - \|\| X		\| VAXBI \|\| [[DSB32]] \|\| colspan="2" \| X (supported DDCMP versions yet unknown) \|\| - \|\| - \|\| X
	\|-		\|-
	\| QBUS \|\| [[DPV11]] \|\| colspan="2" \| X (supported DDCMP versions yet unknown) \|\| - \|\| - \|\| ~~using: VAX Wide Area Network Device Drivers Software~~		\| QBUS \|\| [[DPV11]] \|\| colspan="2" \| X (supported DDCMP versions yet unknown) \|\| - \|\| - \|\| -
	\|-		\|-
	\| QBUS \|\| [[DMV11]] \|\| X \|\| X \|\| X \|\| X \|\| X		\| QBUS \|\| [[DMV11]] \|\| X \|\| X \|\| X \|\| X \|\| X

Vaxorcist: Fixed typo

2025-10-16T06:42:16Z

Fixed typo

← Older revision		Revision as of 06:42, 16 October 2025
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	From 1983 onwards [[serial line]]s (using DDCMP) were step by step superseded by [[Ethernet]], which was superior in terms of speed and flexibility. DDCMP is nevertheless retained in current [[VMS]] DECnet versions, mainly because DDCMP was used still for [[wide area network]]s.		From 1983 onwards [[serial line]]s (using DDCMP) were step by step superseded by [[Ethernet]], which was superior in terms of speed and flexibility. DDCMP is nevertheless retained in current [[VMS]] DECnet versions, mainly because DDCMP was used still for [[wide area network]]s.

	DDCMP usually carried DECnet traffic, one known exception a late VAX version of the [[ULTRIX]] operating system:		DDCMP usually carried DECnet traffic, one known exception is a late VAX version of the [[ULTRIX]] operating system:

	''The [[DMV11]] is supported using TCP/IP and DECnet over full and half duplex point-to-point DDCMP sync lines.''		''The [[DMV11]] is supported using TCP/IP and DECnet over full and half duplex point-to-point DDCMP sync lines.''

Jnc: /* See also */ +Installing and Testing Asynchronous DECnet over DDCMP between two MicroVAX Computers

2025-09-18T02:08:25Z

See also: +Installing and Testing Asynchronous DECnet over DDCMP between two MicroVAX Computers

← Older revision		Revision as of 02:08, 18 September 2025
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	DECnet/VMS only supported asynchronous DDCMP from version 4.0 onwards, i.e., 1984 at the earliest; it was improved with VMS V4.2 in 1985)		DECnet/VMS only supported asynchronous DDCMP from version 4.0 onwards, i.e., 1984 at the earliest; it was improved with VMS V4.2 in 1985)

			==See also==

			* [[Installing and Testing Asynchronous DECnet over DDCMP between two MicroVAX Computers]]

	==External links==		==External links==

Vaxorcist: /* Asynchronous DDCMP */ Correction of the first VMS version to support asynchronous DDCMP

2025-08-21T13:17:09Z

Asynchronous DDCMP: Correction of the first VMS version to support asynchronous DDCMP

← Older revision		Revision as of 13:17, 21 August 2025
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	DECnet-RSX (or DECnet-11M as it was called in the beginning) supported Asynchronous DDCMP at least from Version 2.0 (1979) onwards (see SPD), maybe even right from the start (Infos on DECnet-11M V1.x welcome!).		DECnet-RSX (or DECnet-11M as it was called in the beginning) supported Asynchronous DDCMP at least from Version 2.0 (1979) onwards (see SPD), maybe even right from the start (Infos on DECnet-11M V1.x welcome!).

	DECnet/VMS only supported asynchronous DDCMP from version 4.7 onwards, i.e., ~~1987~~ at the earliest.		DECnet/VMS only supported asynchronous DDCMP from version 4.0 onwards, i.e., 1984 at the earliest; it was improved with VMS V4.2 in 1985)

	==External links==		==External links==

Vaxorcist: /* Asynchronous DDCMP */ Clarified beginning of asynchronous DDCMP on VMS

2025-08-20T14:00:10Z

Asynchronous DDCMP: Clarified beginning of asynchronous DDCMP on VMS

← Older revision		Revision as of 14:00, 20 August 2025
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	DECnet-RSX (or DECnet-11M as it was called in the beginning) supported Asynchronous DDCMP at least from Version 2.0 (1979) onwards (see SPD), maybe even right from the start (Infos on DECnet-11M V1.x welcome!).		DECnet-RSX (or DECnet-11M as it was called in the beginning) supported Asynchronous DDCMP at least from Version 2.0 (1979) onwards (see SPD), maybe even right from the start (Infos on DECnet-11M V1.x welcome!).

	DECnet/VMS ~~started supporting Asynchronous~~ DDCMP ~~not until Version~~ 4.7 ~~as late as~~ 1987.		DECnet/VMS only supported asynchronous DDCMP from version 4.7 onwards, i.e., 1987 at the earliest.

	==External links==		==External links==

Vaxorcist: WAN usage of DDCMP added

2024-10-15T06:43:04Z

WAN usage of DDCMP added

← Older revision		Revision as of 06:43, 15 October 2024
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	It was originally designed by [[Digital Equipment Corporation\|DEC]] for the [[DECnet]] Phase I network [[protocol suite]], in 1974. It was retained in later versions of DECnet, with modifications and extensions.		It was originally designed by [[Digital Equipment Corporation\|DEC]] for the [[DECnet]] Phase I network [[protocol suite]], in 1974. It was retained in later versions of DECnet, with modifications and extensions.

	From 1983 onwards [[serial line]]s (using DDCMP) were step by step superseded by [[Ethernet]], which was superior in terms of speed and flexibility; DDCMP is nevertheless retained in current [[VMS]] DECnet versions.		From 1983 onwards [[serial line]]s (using DDCMP) were step by step superseded by [[Ethernet]], which was superior in terms of speed and flexibility. DDCMP is nevertheless retained in current [[VMS]] DECnet versions, mainly because DDCMP was used still for [[wide area network]]s.

	DDCMP usually carried DECnet traffic, one known exception is [[ULTRIX]]:		DDCMP usually carried DECnet traffic, one known exception a late VAX version of the [[ULTRIX]] operating system:

	''The [[DMV11]] is supported using TCP/IP and DECnet over full and half duplex point-to-point DDCMP sync lines.''		''The [[DMV11]] is supported using TCP/IP and DECnet over full and half duplex point-to-point DDCMP sync lines.''

Vaxorcist: "Software Product Description" link added

2023-09-29T16:15:44Z

"Software Product Description" link added

← Older revision		Revision as of 16:15, 29 September 2023
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	''The [[DMV11]] is supported using TCP/IP and DECnet over full and half duplex point-to-point DDCMP sync lines.''		''The [[DMV11]] is supported using TCP/IP and DECnet over full and half duplex point-to-point DDCMP sync lines.''

	says: "The ULTRIX Operating System, Version 4.5 Software Product Description 26.40.32"		says: "The ULTRIX Operating System, Version 4.5 [[Software Product Description]] 26.40.32"

	==Synchronous DDCMP==		==Synchronous DDCMP==

Vaxorcist: "using: VAX Wide Area Network Device Drivers Software" added

2022-06-15T14:43:15Z

"using: VAX Wide Area Network Device Drivers Software" added

← Older revision		Revision as of 14:43, 15 June 2022
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	\| VAXBI \|\| [[DSB32]] \|\| colspan="2" \| X (supported DDCMP versions yet unknown) \|\| - \|\| - \|\| X		\| VAXBI \|\| [[DSB32]] \|\| colspan="2" \| X (supported DDCMP versions yet unknown) \|\| - \|\| - \|\| X
	\|-		\|-
	\| QBUS \|\| [[DPV11]] \|\| colspan="2" \| X (supported DDCMP versions yet unknown) \|\| - \|\| - \|\| -		\| QBUS \|\| [[DPV11]] \|\| colspan="2" \| X (supported DDCMP versions yet unknown) \|\| - \|\| - \|\| using: VAX Wide Area Network Device Drivers Software
	\|-		\|-
	\| QBUS \|\| [[DMV11]] \|\| X \|\| X \|\| X \|\| X \|\| X		\| QBUS \|\| [[DMV11]] \|\| X \|\| X \|\| X \|\| X \|\| X
	\|-		\|-
	\| QBUS \|\| [[DSV11]] \|\| ? \|\| X \|\| - \|\| - \|\| X		\| QBUS \|\| [[DSV11]] \|\| ? \|\| X \|\| - \|\| - \|\| using: VAX Wide Area Network Device Drivers Software
	\|}		\|}

Vaxorcist: /* Asynchronous DDCMP */ Fixed typo

2022-06-09T10:17:22Z

Asynchronous DDCMP: Fixed typo

← Older revision		Revision as of 10:17, 9 June 2022
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	Asynchronous DDCMP uses simple asynchronous serial lines (such as [[DZ11]] or [[DLV11]]), which are mosty used for terminal communication.		Asynchronous DDCMP uses simple asynchronous serial lines (such as [[DZ11]] or [[DLV11]]), which are mosty used for terminal communication.

	This led to the joke calling it '''"Poor Man's DECnet"''', because asynchronous serial line controllers were much cheaper then synchronous serial ~~line~~ or Ethernet controllers, and many computers already had a spare one available.		This led to the joke calling it '''"Poor Man's DECnet"''', because asynchronous serial line controllers were much cheaper then synchronous serial lines or Ethernet controllers, and many computers already had a spare one available.

	The drawback of Asynchronous DDCMP is lower speed and less effectivity.		The drawback of Asynchronous DDCMP is lower speed and less effectivity.

Vaxorcist: Asynchronous DDCMP added

2022-06-09T10:08:08Z

Asynchronous DDCMP added

@@ Line 81: / Line 81: @@
 | DDCMP TRIBUTARY || Specifies that the line is a multipoint tributary end of a DDCMP multipoint group. You may specify only one circuit per TRIBUTARY line.
 |}
 ==External links==