15 Apr
2012
15 Apr
'12
6:05 p.m.
On Apr 15, 2012, at 8:24 PM, Johnny Billquist wrote:
On 2012-04-16 02:04, David Riley<fraveydank at
gmail.com> wrote:
Hm. Might encourage me to learn some RSX device driver development
once my thesis is done (if I don't finish this semester, I'm pretty
sure my wife will actually murder me).
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...
Hm. Is it possible to split off the UDP portion? I would imagine
that's a much less complex stack, and a lot of the applications I'd
be interested in could be done in UDP fairly easily.
- Dave