Installing and Testing Asynchronous DECnet over DDCMP between two MicroVAX Computers
Asynchronous DECnet over DDCMP has got a nice nickname: "Poor man's DECnet". The reason for this is that it only requires a standard serial interface instead of an expensive network adapter - the price for the software license, however, is the same.
The advantage of this method is that network connections can be established over long distances using modems; the disadvantage is the relatively low speed of a maximum of 19800 baud.
These instructions work on all VAX and MicroVAX computers running VMS V4.x, V5.x, and V6.x and DECnet Phase IV. DECnet Phase V, VMS V7.x and newer as well as VMS/Alpha and VMS/X86 may also work, but have not been tested.
ULTRIX does not support DECnet over asynchronous DDCMP.
Both SIMH VAXen and real VAXen can be connected, and connecting a simh VAX to a real one isn't a problem either.
There are three different ways to configure DDCMP asynchronous DECnet:
- Static asynchronous DECnet
- Dialup static asynchronous DECnet
- Dynamic asynchronous DECnet
For simplicity I choose "static asynchronous DECnet" here, for the other methods see the Recommended Reading below.
I will use two MicroVAX I computers running MicroVMS V4.0 here.
For the first one rename the SIMH executable microvax1 (resp microvax1.exe) to microvax1-1 (resp microvax1-1.exe); for the second one to microvax1-2 (resp microvax1-2.exe).
Contents
Install MicroVMS V4.0 on the first MicroVAX I
Install MicroVMS V4.0 on the first MicroVAX I using this instructions.
Use the following ini file for the first MicroVAX I:
; ================================================ ; microvax1-1.ini ; ================================================ ; ; KD32 CPU ; 2 MSV11-QA = 2MB Memory (or 4 MSV11-PL) ; DZV11 Four-Channel Asynchronous Serial Interface ; RQDX1 Floppy/Fixed Disk Controller ; RX50 400KB 5.25" Dual Floppy Drive ; RD52 31MB 5.25" Fixed Disk SET QUIET SET CONSOLE LOG=uVMS-1_001.log SET CPU IDLE=VMS ; Uncomment the next line if you want a more realistic MicroVAX I speed ;SET THROTTLE 300K SET CPU 2M SET RQ0 RD52 att rq0 uVMS040-1.R52 SET RQ1 RX50 ATT RQ1 BL-B012B-BE.dsk SET RQ2 RX50 SET RQ3 DISABLE SET DZ ENABLE SET DZ LINES=4 ; We'll be using the first serial port (LINE=0) for DECnet. ATT DZ LINE=0,44012,CONNECT=127.0.0.1:44021 SET LPT DIS SET RL DIS SET TS DIS SET XQ ENA SET XQ TYPE=DEQNA BOOT RQ0
Prepare for asynchronous DECnet
Invoke the EDT text editor to add the following commands to your SYSTARTUP.COM file:
$ RUN SYS$SYSTEM:SYSGEN CONNECT NOA0/NOADAPTER EXIT $ SET TERMINAL/EIGHTBIT/PROTOCOL=DDCMP/PERM TTA0:
TTA0: is the name of the terminal port that is connected to the line that you want to make a static asynchronous DECnet-VAX line.
The SET TERMINAL command switches the terminal line to static asynchronous DECnet-VAX.
If more than one terminal is attached to your MicroVMS system, you must add a SET TERMINAL command for each terminal that will be used for static asynchronous DECnet-VAX.
Execute the SYSTARTUP.COM command procedure by entering the following command:
$ @SYS$MANAGER:SYSTARTUP
If you type an error in one of the commands in the first step, SYSGEN does not connect the NOA0/NOADAPTER and you see the following error message when you execute the SYSTARTUP.COM command procedure:
% SYSTEM-W-NOSUCHDEV, no such device available
Configure DECnet
$ @netconfig
DECnet-VAX network configuration procedure
This procedure will help you define the parameters needed to get DECnet
running on this machine. You will be shown the changes before they are
executed, in case you wish to perform them manually.
What do you want your DECnet node name to be? : UVAX1
What do you want your DECnet address to be? : 1.11
Do you want to operate as a router? [NO (nonrouting)]:
Do you want a default DECnet account? [YES]:
Here are the commands necessary to setup your system.
--------------------------------------------------------------------------
$ RUN SYS$SYSTEM:NCP
PURGE EXECUTOR ALL
PURGE KNOWN LINES ALL
PURGE KNOWN CIRCUITS ALL
PURGE KNOWN LOGGING ALL
PURGE KNOWN OBJECTS ALL
PURGE MODULE CONFIGURATOR KNOWN CIRCUITS ALL
$ DEFINE/USER SYS$OUTPUT NL:
$ DEFINE/USER SYS$ERROR NL:
$ RUN SYS$SYSTEM:NCP ! Remove existing entry, if any
PURGE NODE 1.11 ALL
PURGE NODE UVAX1 ALL
$ RUN SYS$SYSTEM:NCP
DEFINE EXECUTOR ADDRESS 1.11 STATE ON
DEFINE EXECUTOR NAME UVAX1
DEFINE EXECUTOR MAXIMUM ADDRESS 255
DEFINE EXECUTOR TYPE NONROUTING IV
DEFINE EXECUTOR NONPRIVILEGED USER DECNET
DEFINE EXECUTOR NONPRIVILEGED PASSWORD DECNET
$ DEFINE/USER SYSUAF SYS$SYSTEM:SYSUAF.DAT
$ RUN SYS$SYSTEM:AUTHORIZE
ADD DECNET /OWNER="DECNET DEFAULT" -
/PASSWORD=DECNET -
Press RETURN to continue
/UIC=[376,376] /ACCOUNT=DECNET -
/DEVICE=SYS$SYSDEVICE: /DIRECTORY=[DECNET] -
/PRIVILEGE=(TMPMBX,NETMBX) -
/FLAGS=(CAPTIVE) /LGICMD=NL: -
/NOBATCH /NOINTERACTIVE
$ CREATE/DIRECTORY SYS$SYSDEVICE:[DECNET] /OWNER=[376,376]
$ RUN SYS$SYSTEM:NCP
DEFINE LOGGING MONITOR STATE ON
DEFINE LOGGING MONITOR EVENTS 0.0-9
DEFINE LOGGING MONITOR EVENTS 2.0-1
DEFINE LOGGING MONITOR EVENTS 4.2-13,15-16,18-19
DEFINE LOGGING MONITOR EVENTS 5.0-18
DEFINE LOGGING MONITOR EVENTS 128.0-4
--------------------------------------------------------------------------
WARNING: no lines have been defined.
Do you want to go ahead and do it? [YES]:
%NCP-I-NMLRSP, listener response - Success
Executor node = 1.11 (UVAX1)
%NML-I-RECDELET, Database entry deleted
%NCP-I-NMLRSP, listener response - Success
Logging sink type = monitor
%NML-I-RECDELET, Database entry deleted
%NCP-I-NMLRSP, listener response - Success
Logging sink type = monitor
%NML-I-RECADDED, Database entry added
The changes have been made.
If you have not already installed the DECnet-VAX license, then do so now.
After the license has been installed, you should invoke the procedure
SYS$MANAGER:STARTNET.COM to startup DECnet-VAX with these changes.
(If the license is already installed) Do you want DECnet started? [YES]:
%RUN-S-PROC_ID, identification of created process is 00000019
%RUN-S-PROC_ID, identification of created process is 0000001B
After running the NETCONFIG.COM command procedure and before starting the network, run the Network Control Program (NCP) by entering the following commands:
$ RUN SYS$SYSTEM:NCP NCP> DEFINE LINE dev-c-u STATE ON RECEIVE BUFFERS 4 NCP> DEFINE CIRCUIT dev-c-u STATE ON NCP> EXIT
where:
-
devis the first two letters of the device name. Possible values for dev are TT and TX. -
cis a decimal number(0 or a positive integer) designating a device’s hardware controller. If the third letter of the device name is A, c equals 0. If the third letter of the device name is B, c equals 1, and so on. -
uis the unit number of the device name; u is always equal to 0 or a positive integer. -
baud-rateis the speed at which the line sends and receives data.
There are two common types of asynchronous serial adapters:
- DZV11/DHV11/DZ11 - the VMS port device names begin with
TT - DHQ11/DHU11 - the VMS port device names begin with
TX
For example, to use a device named TTA0 at 9600 baud, run NCP and enter the following commands:
$ RUN SYS$SYSTEM:NCP NCP> DEFINE LINE TT-0-0 STATE ON RECEIVE BUFFERS 4 NCP> DEFINE CIRCUIT TT-0-0 STATE ON NCP> EXIT
Start DECnet
$ @SYS$MANAGER:STARTNET
Shutdown first MicroVAX I
$ SHUTDOWN
SHUTDOWN -- Perform an Orderly System Shutdown
%SHUTDOWN-I-OPERATOR, This terminal is now an operator's console.
%SHUTDOWN-I-DISLOGINS, Interactive logins will now be disabled.
%SET-I-INTSET, login interactive limit = 0, current interactive value = 1
%SHUTDOWN-I-SHUTNET, The DECnet network will now be shut down.
%SHUTDOWN-I-STOPQUEMAN, The queue manager will now be stopped.
SHUTDOWN message on UVAX1 from user SYSTEM at _OPA0: 12:00:19
UVAX1 will shut down in 0 minutes; back up LATER. Please log off node UVAX1.
SHUTDOWN
1 terminal has been notified on UVAX1.
%SHUTDOWN-I-STOPUSER, All user processes will now be stopped.
%SHUTDOWN-I-REMOVE, All installed images will now be removed.
%SHUTDOWN-I-DISMOUNT, All volumes will now be dismounted.
SYSTEM SHUTDOWN COMPLETE - USE CONSOLE TO HALT SYSTEM
Infinite loop, PC: 80008D7E (BRB 80008D7E)
sim> exit
Goodbye
Log file closed
Prepare the second MicroVAX I
Copy the RD52 image of the first MicroVAX I for the second MicroVAX I using its new name uVMS040-2.R52
Use the following ini file for the second MicroVAX I:
; ================================================ ; microvax1-2.ini ; ================================================ ; ; KD32]] CPU ; 2 MSV11-Q|MSV11-QA = 2MB Memory (or 4 MSV11-PL) ; DZV11 Four-Channel Asynchronous Serial Interface ; RQDX1 Floppy/Fixed Disk Controller ; RX50 400KB 5.25" Dual Floppy Drive ; RD52 31MB 5.25" Fixed Disk SET QUIET SET CONSOLE LOG=uVMS-2_001.log SET CPU IDLE=VMS ; Uncomment the next line if you want a more realistic MicroVAX I speed ;SET THROTTLE 300K SET CPU 2M SET RQ0 RD52 ATT RQ0 uVMS040-2.R52 SET RQ1 RX50 ATT RQ1 BL-B012B-BE.dsk SET RQ2 RX50 SET RQ3 DISABLE SET DZ ENABLE SET DZ LINES=4 ; We'll be using the first serial port (LINE=0) for DECnet. ATT DZ LINE=0,44021,CONNECT=127.0.0.1:44012 SET LPT DIS SET RL DIS SET TS DIS SET XQ ENA SET XQ TYPE=DEQNA BOOT RQ0
Configure DECnet on the second MicroVAX I
Boot second MicroVAX I and log in as SYSTEM.
Shutdown DECnet.
$ MC NCP SET EXEC STATE SHUT
Configure DECnet
$ @netconfig
Configure serial line TTA0: from DCL and network line LINE TT-0-0 from NCP as you did for the MicroVAX I.
Monitoring DECnet
Display state of asynchronous DDCMP serial interface TTA0:
$ SHOW DEVICE TTA0: /FULL
Terminal TTA0:, device type unknown, is online, record-oriented device, carriage
control, network device.
Error count 0 Operations completed 12297
Owner process "NETACP" Owner UIC [SYSTEM]
Owner process ID 00000026 Dev Prot
Reference count 2 Default buffer size 576
$
List DECnet lines
$ MC NCP SHOW KNOWN LINES Known Line Volatile Summary as of 30-AUG-2025 08:52:16 Line State TT-0-0 on $
Display DDCMP DECnet line TT-0-0
$ MC NCP SHOW LINE TT-0-0 CHAR Line Volatile Characteristics as of 30-AUG-2025 08:52:34 Line = TT-0-0 Receive buffers = 4 Controller = normal Duplex = full Protocol = DDCMP point Retransmit timer = 3000 $
Display local DECnet node UVAX1 counters
$ MC NCP SHOW NODE UVAX2 COUNTERS
Node Counters as of 30-AUG-2025 08:50:38
Executor node = 1.12 (UVAX2)
>65534 Seconds since last zeroed
253 Bytes received
250 Bytes sent
28 Messages received
29 Messages sent
1 Connects received
1 Connects sent
0 Response timeouts
0 Received connect resource errors
4 Maximum logical links active
0 Aged packet loss
0 Node unreachable packet loss
0 Node out-of-range packet loss
0 Oversized packet loss
0 Packet format error
0 Partial routing update loss
0 Verification reject
$
Display remote DECnet node UVAX1 counters
$ MC NCP SHOW NODE UVAX1 COUNTERS
Node Counters as of 30-AUG-2025 08:50:18
Remote node = 1.11 (UVAX1)
>65534 Seconds since last zeroed
561 Bytes received
5863 Bytes sent
2367 Messages received
2359 Messages sent
2 Connects received
0 Connects sent
19 Response timeouts
0 Received connect resource errors
$
List DECnet links
$ MC NCP SHOW KNOWN LINKS Known Link Volatile Summary as of 30-AUG-2025 08:51:19 Link Node PID Process Remote link Remote user 4 1.11 (UVAX1) 00000029 REMACP 2 SYSTEM $
Display DECnet link 4
$ MC NCP SHOW LINK 4 CHAR Link Volatile Characteristics as of 30-AUG-2025 08:51:54 Link = 4 State = run PID = 00000029 Remote node = 1.11 (UVAX1) Delay time = 1 Remote link = 2 Remote user = SYSTEM Username = SYSTEM Process name = REMACP $
References
See also
Related VMS Manuals
Recommended Reading
External links
- AA-FW62A-TN MicroVMS User's Manual Part 1 V4.2 Not online!
- MicroVMS VAXstation 2000/MicroVAX 2000 Installation Guide (AA-JR84A-TN)
