24 Mar
2016
24 Mar
'16
6:53 p.m.
On Mar 23, 2016, at 12:00 PM, cctech-request at classiccmp.org wrote:
Message: 2
Date: Tue, 22 Mar 2016 16:34:01 +0100
From: Mattis Lind <mattislind at gmail.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: RSX11S
Message-ID:
<CABr82SKAPr=Ck92GKPmog9S64GSe2D2Z47A7yS-mFpAeKcGptg at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
While archiving a bunch of old 8 inch disks I found disks that apparently
contain an old RSX11S system. I think it has been used in some kind of
railroad CTC system.
https://dl.dropboxusercontent.com/u/96935524/Datormusuem/PDP11RX01DISKS/DIS…
It is possible to boot this image in SimH (when setting CPU type to 11/03,
11/23 (F11), 11/34 or 11/73 (J11) )
I get this:
sim> b rx0
XDT: 18
XDT>g
RSX-11S V02 BL18
DEVICE TT01: NOT IN CONFIGURATION
DEVICE FT00: NOT IN CONFIGURATION
So first there is a XDT> prompt. By pressing g or p it starts RSX11S. But
it seems to be possible to do other things. Commands like "s" and "l"
do
stuff "x" causes:
XDT>x
SYSTEM CRASH AT LOCATION 025276
REGISTERS
R0=000000 R1=177170 R2=003403 R3=157000
R4=012422 R5=000002 SP=157004 PS=000340
SYSTEM STACK DUMP
LOCATION CONTENTS
157004 157150
HALT instruction, PC: 000572 (MOVB #15,R2)
sim>
I understand that RSX11S is a scaled down version of RSX11M. An embedded
RTOS of that day. But what kind of commands are possible at the XDT and
MCR(?) prompts. I am a little bit curious to understand more about the
system that it has been running.
/Mattis
Mattis,
A good description of what is possible in RSX11S can be found in the manual:
http://bitsavers.trailing-edge.com/pdf/dec/pdp11/rsx11/RSX11S_V4.2_Jul85/AA…
Because you got the MCR - 1 (Illegal Function) response I think basic MCR must have
been included in the system. The XDT> is the eXecutive Debugging Tool and is similar to
ODT. The X is a command to do a crash dump.
There are not many MCR commands available in RSX11S, but one that you should try is TAL
which if it was included in the system sysgen will display all the installed tasks and
their status, ATL shows which tasks are active. RUN task name will execute a task that is
installed.
The most interesting thing that you might find in the system, if it was included is a task
called RSDV1H which displays a live picture of the memory organization and system
operation similar to RMD on a RSX11M or M+ system.
RSX11S was designed to be a memory resident real-time priority driven multitasking
system. It is booted from a disk but really doesn't have a file system unless it is
included in the sysgen and then it only does block I/O type operations. Nonresident tasks
can be loaded by a task loader if that capability is sysgened in.
This all sounds pretty limiting and it is but still RSX11S can do a lot when needed.
Over 30 years ago, I helped create a system that read data from 8 commodity exchanges
& a news wire feed in various formats, then sent DECnet data packets to 10 PDP-11/23s
running RSX11S. The 11/23s each had 20 VT100s hung off each one (using DLV11Js and DZV11s)
with each commodity trader getting customized screens of data in real-time. The goal was
to get data to the traders faster than any other commercial service. News headlines
scrolled across the bottom of the VT100 and the trader could request specific stories
which were stored in a RMS-11 Indexed file back on the main server which was an 11/44 run
RSX11M. The RSX11S systems had no disk and were downloaded the OS over the leased data
line running at 9600 baud (fast for the day). The 11/23s ran re-entrant Macro-11 code in
256 Kbytes of RAM (OS, programs, & DECnet).
Best Regards,
Mark
a
MCR -- 1
b
MCR -- 1
ccc
MCR -- 1