SimH simulating a PDP-11 with two ethernet Adapters: One for DECnet and one for TCP/IP on PDP-11/93 RSX-11M-PLUS Version 4.6 Base level 87 (QBUS, 2 x DEQNA) - SYSGEN NETGEN IPGEN log / terminal sessions

I have been playing around with a SimH PDP-11/24 running RSX-11M-Plus 4.6 from 2016. A fairly complete installation with DECnet networking, BASIC PLUS 2, DIBOL, PASCAL, C AND COBOL language support, it was nonetheless missing TCP/IP connectivity. This month I finally got around to giving it a refresh, upgrading to a PDP-11/93 (the fastest QBUS PDP-11) with dual network adapters and a DPV11 line for DDCMP. (SimH support for DPV11 is, however, currently a work in progress; hopefully a future version of SimH will incorporate complete DPV11 support to allow some fun with DDCMP without having to switch to UNIBUS machine).

Thanks to the efforts of others, I did not have to reinstall RSX from grounds up once again. A fully configured PDP-11/70 including BQTCP and lots of software is available for download at www.rsx11m.com (look for the links saying "Download PiDP-11 DU0 RSX11M+ V4.6 w/ BQ TCP/IP" and "Download PiDP-11 DU1 containg RSX Sig Tapes"). This distribution, itself based on the PiDP-11 project distribution, is perfect for starting off a UNIBUS PDP-11/70 machine ripe for SYSGEN/NETGEN/IPGEN into whatever PDP-11 model one desires.

The following SYSGEN, NETGEN and IPGEN phases were performed on a fresh install of the downloaded and configured PDP-11/70. LB:[1,2]LOGIN.TXT in the logs below still show "PiDP-11/70 PiDP11" and was corrected later on.

SYSGEN

SYSGEN does not allow for more than one ethernet adapter. The NETGEN procedure, however, does allow dual network adapters. For SYSGEN, the answer is 1 for this question:

>;   XE:    controller:  DEUNA
>;
>; The Digital Equipment UNIBUS Network Adapter (DEUNA) is a data
>; communications controller used to interface PDP-11 family computers
>; to the Ethernet local area network.
>;
>* CP8504  How many DEUNA Ethernet controllers do you have? [O R:0-1 D:0]: 1

NETGEN

In NETGEN, we get to specify two network adapters. We also do not bring up QNA-1 automatically because QNA-1 will not have DECnet on it, only TCP/IP as we specify during the IPGEN phase next.

>* 01.00 Device Driver Process name [<RET>=Done] [S R:0-3]: QNA
>* 02.00 How many QNA controllers are there [D R:1.-2. D:1.]: 2
>* 02.01 Are all QNAs installed at the same device priority [D=N]? [Y/N]: Y
>* 02.02 What is the QNA device priority [O R:4-6 D:5]:
>;
>* 03.01 CSR address for QNA-0 [O R:160000-177777 D:174440]: 174440
>* 03.02 Vector address for QNA-0 [O R:0-774 D:120]: 120
>;
>* 04.07 Set the state for QNA-0 ON when loading the network [D=N]? [Y/N]: Y
>;
>* 03.01 CSR address for QNA-1 [O R:160000-177777 D:174460]: 174460
>* 03.02 Vector address for QNA-1 [O R:0-774 D:130]:
>;
>* 04.07 Set the state for QNA-1 ON when loading the network [D=N]? [Y/N]: N

IPGEN (BQTCP)

The documentation included with his BQTCP distribution is impeccable. Once a second adapter dedicated to TCP/IP was available (QNA-1 in this case), IPGEN wasn't difficult to execute at all.

DEC VAX/VMS 3.5 with DECnet Phase IV networking (DECnet-VAX V3.0, VMS V3.5): Revisiting "VAX/VMS Version V3.5 17-NOV-1983 16:21"

 

With substantial hand-holding by the folks at HECnet,  I managed to bring up a SimH VAX-11/780 running ancient VAX/VMS version 3.5 with DECnet Phase-IV networking running over Ethernet, learning a few things on the way.

The only two media really needed are (a) VAX/VMS 3.5 installation tape "BB-D782F-BE" and (b) DECnet license installation medium "BE-X083A-BE_-_DECNET-VAX_FULL_FUNCTION_V3.1" containing "NETRTG031.A". While exploring the latter, I learned about TU58 DECtape II, a "random-access, fixed-length-block, mass-storage tape system" from October of 1978 that "uses preformatted tape cartridges which store 262 kilobytes of data in 512-byte blocks" accessible "in a fashion similar to data stored on disks or DECtape". "A file-oriented structure is easily implemented in an operating system by setting aside several blocks on the tape to store a directory", which means its a tape that works like a very slow tiny 262 kb hard-disk!

  VAX/VMS Version V3.5 17-NOV-1983 16:21

Just to make installation simpler, I copied the installation files from both media onto a RD54 159MB Winchester hard disk using another SimH VAX. The installation session captured below uses that hard disk instead of two separate tape and TU58 media. (The installation files are also available from the FAL area of the installed VAX/VMS 3.5 node XXXV {31.42} accessible over HECnet.) It is of course possible to perform the same installation from VAX/VMS 3.5 distribution tape attached to MSA0: and DECnet license TU58 attached to TDC0:.

$ dir xxxv::
Directory XXXV::SYS$SYSDEVICE:[DECNET]
EDTCAI.SAV;1        EDTCAI1.SAV;1       LIBRARY.;1          NETACP35.EXE;1
NETRTG031.A;2       NETRTG040.A;1       NETSERVER.LOG;14    NETSERVER.LOG;13
NETSERVER.LOG;12    OPTIONAL.;1         REQUIRED.;1         VMSOPT.SAV;1
Total of 12 files.

"DECnet-VAX V3.0,  VMS V3.5" is somewhat unusual, even a little buggy. The DECnet configurator command file SYS$MANAGER:NETCONFIG.COM presents a choice of node address from the range of 1 through 1023 indicating a DECnet Phase-III implementation, but it happily accepts a Phase-IV <area>.<node> format address with no complaints:

What do you want your DECnet address to be?    [1-1023]: 31.42

This is despite support for Phase-IV style areas in the Executor characteristics. The executor can be configured with MAXIMUM AREA set to its maximum 63 with no complaints either, indicating full support of Phase-IV. Another quirk is that NCP HELP SET shows a list devoid of any SET MAXIMUM AREA, although that command works fine.

NCP>SHOW EXEC CHAR

Node Volatile Characteristics as of 18-DEC-2021 18:12:04

Executor node = 31.42 (XXXV)

Identification           = DECnet-VAX V3.0,  VMS V3.5

Management version       = V4.0.0

Incoming timer           = 45

Outgoing timer           = 45

NSP version              = V3.2.0

Maximum links            = 32

Delay factor             = 80

Delay weight             = 5

Inactivity timer         = 60

Retransmit factor        = 10

Routing version          = V2.0.0

Type                     = routing IV

Routing timer            = 600

Broadcast routing timer  = 40

Maximum address          = 1023

Maximum circuits         = 16

Maximum cost             = 1022

Maximum hops             = 30

Maximum visits           = 63

Maximum area             = 63

Max broadcast nonrouters = 64

Max broadcast routers    = 32

Area maximum cost        = 1022

Area maximum hops        = 30

Maximum buffers          = 100

Buffer size              = 576

Nonprivileged user id    = DECNET

Default access           = incoming and outgoing

Pipeline quota           = 1200

However, the DECnet implementation is clearly buggy in a negative way for DDCMP links. It does not send the Area part of it's Phase-IV address to its DDCMP peer (just sends 42 instead of 31.42). The DDCMP circuit DMC-0 for this installation had to be turned off to avoid a continuous series of operator messages as the DDCMP circuit repeatedly tries to establish adjacency using only half of the DECnet address.

It would appear the stock DECnet that shipped with VAX/VMS V3.5 was Phase-III only, and the License / Patch NETRTG031 bumps it up to DECnet Phase-IV but they forgot to upgrade and test DDCMP code as well with the patch. As a result, the patch works fine with Ethernet circuits but is broken for DDCMP circuits.

Here is the terminal session log of installation on a SimH-emulated VAX 11/780 of the ancient but very capable VAX/VMS 3.5 operating system with DECnet Phase-IV. It includes the SimH configuration file vax780.ini. A tarball of the experimental SimH instance is available for download from my gopher server or dropbox.

RT-11 on PDP-11/45 Adventures: Running SYSGEN

DEC PDP-11/45, picture from www.pdp-11.nl

So I stumbled my way through running SYSGEN for Digital Equipment Corp's DEC RT-11 operating system on a SimH PDP-11/45. Here is the full session log, with  no attempt at removing the mistakes made.