Web server running on RSX-11M-PLUS - test-drb@ccmp.vtda.org

15 Apr 2012

On 2012-04-16 02:04, David Riley<fraveydank at gmail.com> wrote:

...
  On Apr 14, 2012, at 11:11 AM, Johnny Billquist wrote:

  >  On 2012-04-13 19:00, "Zane H.
Healy"<healyzh at aracnet.com>  wrote:
> >>  Not sure why I didn't see the original.  I have to agree, this is
> >>  *VERY*   cool, as I suspect very few hobbyists have access to a TCP
> >>  stack for RSX-11M+ at this point!  This is also the first I've heard
> >>  of a web server hosted on a PDP-11 running on something other than
> >>  RT-11.
> >>
> >>  Are you targeting a specific Ethernet interface?
 >
 >  Nope. Works fine on both Q-bus and Unibus machines. However, with Q-bus, you need
DECnet for now, for the Ethernet interface, while for Unibus you can either go with
DECnet, or else the supplied Ethernet driver in the system.
 >
 >  And yeah, I have only seen the RT-11 webserver up until now.
 >
 >  More to come...  Yes, this is super-exciting!  Now, when you mentioned it was
too big
 for non-split I&D, was that the whole web task + IP stack, or was the
 stack alone too big?  I have an 11/23 (I also don't have enough RAM
 to run RSX-11M+, but that's a little more easily rectified). 
Unfortunately it's specific bits of the stack that are too large. If it 
had been the combination, then it would not have been a problem. RSX 
don't have a problem with several tasks combined using plenty of memory. 
It is individual bits that are limited to 64K.
And actually, the story goes on a little further. To make a long story 
short, a device driver in RSX is normally limited to 4 KW. You can 
extend that to 8KW by a little fiddling. Unfortunately, my TCP driver 
needs more than 4KW of instruction space, and then 4 KW of data space as 
well, which is the problem. In M+, I can handle this, since I- and 
D-space are separate, so the TCP driver works with just a little 
fiddling. In 11M, I would have to do some serious rewriting and possibly 
manual overlaying in order to make it work. It is possible, and there 
are some device drivers that actually do this kind of stuff (most 
notably the terminal device driver). But it is a rather complex task to fix.

And it is actually only the TCP driver that is the problem. Evert other 
component fits withing the existing address space allowed even with 
split I- and D-space.

But then again, the TCP code is the most complex piece...

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol