Friday, March 8, 2019

Deploying a PDP-11/73 running RSTS/E 10.1 with DECnet/E 4.1 Networking Using SIMH

SANYALnet Labs: Supratim Sanyal's Hobbyist PDP-11/73 Micro PDP-11 running RSTS/E Operating System with DECnet/E networking
DEC PDP-11/73 (Picture courtesy: Field-One)
I finally got around to adding a SIMH PDP-11/73 node "RST101" running RSTS/E operating system version 10.1 with DECnet/E 4.1 to my retro-computing hobbyist lab. Marketed by DEC as a "MicroPDP", the PDP-11/73 featured 15.2 MHz DEC J-11 microprocessor chip-set with Q-Bus and supported a maximum of 4 MB of memory.

SANYALnet Labs: SIMH Digital Equipment Corporation PDP-11/73 running RSTS/E 10.1 Operating System with DECnet/E 4.1 networking
Digital Equipment Corporation PDP-11/73 running RSTS/E 10.1 Operating System with DECnet/E 4.1 networking
The RSTS/E and layered software distribution tapes are available at this FTP server. The SIMH PDP-11 emulator was built along with other VAX and PDP emulators from the latest SIMH source code (PDP-11 simulator V4.0-0 Current git commit id: 314a1da9) using the following make command line:

$ make USE_READER_THREAD=1 USE_TAP_NETWORK=1 USE_INT64=1 pdp1 pdp4 pdp7 pdp8 pdp9 pdp15 pdp11 pdp10 \
        vax microvax3900 microvax1 rtvax1000 microvax2 vax730 vax750 vax780 vax8600

Access via DECnet to other nodes in my lab network as well as HECnet is via a Virtual Distributed Ethernet Switch (VDE) plug.


The RSTS/E 10.1 node with DECnet nodename "RST101" is accessible from HECnet over RTERM (not default CTERM) protocol. When using the "SET HOST" command from VMS or OpenVMS for example, the application protocol needs to be specified to be RTERM.

There is a guest account [210,1] with no password for interested folks to experience RSTS/E. Here is an example session initiated from another OpenVMS/VAX 7.3 node on HECnet:

%REM-I-CONNECTION, connection made using RTERM protocol
%REM-I-REMOTE, connection established to remote node RST101::
RSTS V10.1-L 15-Mar-19 10:01 PM
User: 210,1
Last interactive login on 15-Mar-19, 10:01 PM at KB21:

System name:                     RSTS V10.1-L RSTS/E V10.1
Date format:                     Alphabetic
Time format:                     AM_PM
Magtape label default:           DOS
Magtape density default:         1600 BPI
Power fail restart delay:        300 seconds
Dynamic Region Limit:            0K words
Hangup:                          Delayed
Monitor Statistics:              Disabled
Job limit:                       10
Current jobs:                    7
LAT Software:                    Installed
FMS Software:                    Not Installed
Current Pseudo keyboards:        4
Answerback message:              None

Memory allocation table:
 Start   End  Length  Permanent   Temporary
   0K -   91K (  92K) MONITOR    
  92K - 1734K (1643K)   (User)   
1735K - 1744K (  10K)   (User)    DAPRES LIB
1745K - 1748K (   4K)   (User)    RMSRES LIB
1749K - 2043K ( 295K) ** XBUF ** 
2044K -  *** END ***
Saved all disk files on SY: 0 blocks in use
Job 7 User 210,1 logged off KB21: at 15-Mar-19 10:01 PM
System RSTS V10.1-L RSTS/E V10.1
Run time was 0 seconds
Elapsed time was 0 minutes
Good evening

%REM-S-END, control returned to node QCOCAL::

Miscellaneous information

The system directory [0,1] contains:

$ dir [0,1]

 Name .Typ    Size    Prot     Name .Typ    Size    Prot     Name .Typ    Size    Prot     Name .Typ    Size    Prot    SY:[0,1]
BADB  .SYS       0 P < 63>    SATT  .SYS      14CP < 63>    INIT  .SYS     618CP < 60>    BACKUP.TSK     146C  <232>
CONFIG.SYS       1CP < 60>    DCL   .RTS     114C  <232>    ERR   .ERR      16CP < 40>    GETSYS.TSK      56C  <124>
PKG001.MSG       8C  < 40>    PKG002.MSG       7C  < 40>    RSX   .RTS       6C  < 60>    SYSGEN.SIL     686C  < 60>
CRASH .SYS    1360CP < 63>    ASSLOG.COM      13C  <104>    BEGIN .COM      34C  <104>    CHECK .COM       3C  <104>
COPYUP.COM       2C  <124>    CSP   .COM      36C  <104>    CSP   .HLP       2C  <104>    CSP1  .HLP       1C  <104>
CSP100.LIB      41C  < 60>    CSP2  .HLP       2C  <104>    CSPHLP.COM       9C  <104>    CSPLIB.LIB      41C  < 60>
CSPLNG.COM      24C  <104>    CSPLST.DAT       2C  <104>    CSPRES.COM      17C  <104>    DELLOG.COM       4C  <104>
INSPKG.COM      14C  <104>    INSTAL.COM       3C  <124>    LISTER.COM       8C  <104>    LP    .COM      23C  <104>
LP    .HLP       2C  <104>    LP1   .HLP       1C  <104>    LP2   .HLP       1C  <104>    LPRES .COM      13C  <104>
LPX   .HLP       1C  <104>    LPX1  .HLP       1C  <104>    MAIN  .COM      23C  <104>    MICRO .HLP       2   < 60>
MONBLD.COM      16C  <104>    MONITR.COM      17C  <104>    NETCHK.TSK      13C  <124>    NETDEL.COM       9C  <104>
ODT   .SYS      14   < 60>    RECOVR.COM      12C  <124>    REMESC.TSK      13C  <124>    RT11  .RTS      20C  < 60>
SETPAS.COM       2C  <104>    SYSINI.COM       8C  <124>    UPDATE.COM       3C  <124>    VOLCHK.COM       5C  <104>
SWAP1 .SYS    2376CPL< 60>    MICRO .SIL     648CP < 60>    LOGIN .COM       5C  <104>    START .COM      21C  <124>
BASIC .RTS      65C  < 60>    SWAP  .SYS     264CP < 63>    NETPRM.SYS     821C  <188>    NSP0  .SYS     821C  <188>
NOTICE.TXT       1   < 60>    

Total of 8509 blocks in 61 files in SY:[0,1]

Here is my SIMH .ini file:

Here is the screen session for installing RSTS/E on DEC PDP-11/73 SIMH emulator:

and finally, screen session for installing DECnet/E:


  1. Hi!
    Trying to install decnet according to this guide.
    However when doing: att xq tap:dnettap0
    I get the error message:
    Eth: opened OS device dnettap0
    Sat Aug 1 22:29:45 2020
    Sockets: _eth_write(tap): error 5 - Input/output error
    XQ: Eth: Error Transmitting packet: Input/output error
    You may need to run as root.

    The modules TUN and TAP are loaded and running as root does not help.
    any idea what I am missing?

  2. Hi,
    Operating system?
    SIMH version?
    How exactly is dnettap0 being created?
    What does ifconfig dnettap0 show?

    1. OS is slackware 14.2 but kernel updated to 5.2.2
      ../simh-master/BIN/pdp11 -V
      PDP-11 simulator V4.0-0 Current git commit id: 6fdc4474

      Have not done any action other than in your example to create dnettap0, so that must be the reason.

      ifconfig dnettap0
      dnettap0: error fetching interface information: Device not found

      So any pointer to how to create dnettap0 would be appreciated.

    2. There are numerous tun/tap discussions online to get you started; I found this, for example:

    3. Thanks, seems that part is working now... Now to see how to config pydecnet...


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