How to transfer data FAST?

Johnny Billquist bqt at Update.UU.SE
Mon Jun 27 09:25:10 CDT 2005


On Mon, 27 Jun 2005 Paul Koning <pkoning at equallogic.com> wrote:

> >>>>> "Johnny" == Johnny Billquist <bqt at Update.UU.SE> writes:
>
>  Johnny> On Wed, 22 Jun 2005 Paul Koning <pkoning at equallogic.com>
>  Johnny> wrote:
>
>  >> Ethernet is another good way; DECnet is available on Linux.
>
>  Johnny> Unfortunately, the DECnet for Linux sucks so bad it isn't
>  Johnny> usable. Well, it is kindof usable if you want to talk with a
>  Johnny> VMS machine, but it don't work against RSX. I've tried
>  Johnny> it... :-(
>
> So try it with RSTS...

Don't have RSTS. :-)

>  Johnny> Appearantly the DECnet/Linux guys only have had VMS machines
>  Johnny> to test against, and I didn't manage to stir much interest
>  Johnny> when I reported how badly it failed with RSX. I only got
>  Johnny> responses like "well, that don't surprise us, since we've
>  Johnny> only tested against VMS".
>
> Hard to blame someone for having it not work on a system they can't
> test.  It's open source -- you can fix it, and contribute your fixes.
> That's what I did.

True, and definitely a point for you.
I offered them access to systems to check it out, but no interest. Myself,
I'm not interested in Linux enough for this. I'm doing the TCP/IP for RSX
instead.

> Part of the problem is at the DEC end -- undocumented hacks in DAP
> (VMS is particularly bad there) and the totally undocumented pre-CTERM
> "set host" protocols.

I know... :-/
RSX actually have a different program for each DEC OS that exist, to use
instead of the "normal" CTERM program. Unsupported, of course, but working
much better...

DAP basically failed in three of the four tests I did between Linux and
RSX. File transfers in both directions, and directory listings in both
directions. The one that did work was directory listings of the RSX system
from Linux. I think I might have been able to transfer some trivial text
files from RSX to Linux as well, but that was it. Everything else failed,
or rather, just hung.

On a separate issue, the public domain LAT is equally problematic, and
should not be used to connect to RSX hosts. You'll crash the RSX host
eventually. That LAT implementation seem to produce some packets that RSX
just don't deal with, which results in buffer pool getting lost on the RSX
end. It's definitely not a good behaviour in RSX as well, but never the
less, it appears as if the PD LAT breaks the protocol in some way, and LAT
is even worse, since no documentation exists outside of DEC (or
whereever), so it's all reverse engineering (once more of VMS).

Maybe one day...
Or if I get my hands on the sources to RSX DECnet and LAT, I could do some
cleanups in there... But that will not likely happen anytime soon I'm
afraid...

Ah, and there is also a bug in the DAP code in RSX. I have a patch for
both RMSDAP.OLB and DAPRES. The problem is that the file protection word
gets messed up when read.

	Johnny

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



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