New subject: Multi-User BASIC

1 Apr 1999

...
   Well, since it was in the rack and feeling lonely and
neglected, I 
fired up my 11/73 tonight; the first example of DEC stuff I ever 
owned. It is not in a DEC chassis, actually it is only about 40 
percent DEC.  It is running RT11SJ V5.01.  It has a full-height 5" 
HD as DL: and one 8" floppy as DY: (RX02).  It was used in a speech 
pathology research lab and all that software is still on it, tho 
I've no idea how to invoke it at this time. It has the usual 
Fortran, Basic, and Cobol systems.  I've used the Basic interpreter 
to write some little programs just to play with it.

  It also has an RSX runtime system on it, but it asks for a 
user/password which of course I don't have.  Anyone have any idea 
how to defeat this? 
RSX Runtime system?  Under RT-11?  Or on a separate disk?
Passwords on an RT system?  Not normally... you may be running
some special software...

...
   I am looking for the following: The 11/73 Processor
manual. An 
RL11-type controller card so I can hook up an RL02 to it.  
Information on how to determine/configure the port assignments..  I 
would like to have a line printer device and also a modem (for 
Kermitting) but it has 8 ports on two cards, one of which is the 
console port I found by repeatedly booting the system and watching 
port pins with a scope. 
Sounds like a couple of DLV11-Js... 4 line serial async cards.

...
   The model of the SLUs escapes me at the moment, and
I'm too tired
to go pull the thing out from the rack and take the back off and get
the numbers.  I just want to know how RT11 assigns and communicates
with it's ports.  
M8043 if it is a DLV11-J...

As for configurating the ports, the console always has to be at
the address 177560, with a vector of 60.  The DLV11-J allows one
of the ports to be the console.  The other ports are configured
for successive addresses in the range 176500 and up, with the
vectors in the floating range (300-476).

You're going to need to let us know what boards you really have,
and then we can tell you what documentation you'll need to
configure them.

I would suspect, however, that it has already been configured for
the software you have on it.

RT-11 as distributed only knows about one terminal - the console,
at the standard address.  To support more than one terminal, you
would have to do a sysgen (system generation, in which a new
monitor is built using conditionals specified to the sysgen
procedure).  But remember, RT-11 is single-user, so even if you
have multiple terminals, only one can be the console, and only
the console can initiate programs.  Such programs *can* then
allocate the other terminals and control them (such as in the
multi-user BASIC which is available for RT-11)

					Megan Gentry
					Former RT-11 Developer

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PDP 11/73