[comp.windows.x] Alternate transport for X-protocol, also Sockets for VMS

dvb@emisle.emisle (David Van Beveren) (02/14/91)

I have an interesting problem on my hands. Someone wants to run X on a
wide area X.25 network that supports tli. Has anyone converted X11R4 server
and Xlib to support this or any other transport. From looking at the server
source it should not be too difficult at that end.

The MIT tapes have support for tcp, unix-domain and DECnet, all implemented
as BSD sockets. Did someone at DEC (or elsewhere?) implement a VMS DECnet
interface, or does the VMS version of X11R4 use a Berkeley sockets library?
If the latter, where can I get a copy of that library?

I know these are two completely different questions, but if you know the
answer to either or both, then please e-mail. I will post summary if there
is interest.

dvb
-- 
David Van Beveren                           INTERNET: emisle!dvb@ism.isc.com
EIS ltd. Professional Software Services     UUCP:   ..uunet!emisle!dvb
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randy@erik.UUCP (Randy Brown) (02/19/91)

David Van Beveren                           INTERNET: emisle!dvb@ism.isc.com
>I have an interesting problem on my hands. Someone wants to run X on a
>wide area X.25 network that supports tli. Has anyone converted X11R4 server
>and Xlib to support this or any other transport. From looking at the server
>source it should not be too difficult at that end.
 
Look a little more closely, and on the R4 tape you will find another connection
option in addition to BSD sockets, accessed by -DSTREAMSCONN.  This works just
fine as local transport (if both server and client are built to expect it, of
course) and as TCP/IP on Ethernet.  I don't have a TLI-compliant X.25, but it
should work there just fine.

It works in a network-independent fashion by looking up the requested display
in a file, getting back host and network name.  Then it calls a daemon over
local streams transport; the daemon forks and execs the name/address server
appropriate for the requested network, which returns a TLI address to the 
X client.  That way the client doesn't need to know anything at all about
the network's peculiarities.  The system administrator builds the table and
installs the nameservers appropriate to the local system.  AT&T's binaries 
work over both Ethernet and their 1Mbps Starlan, so it should be possible 
to produce a binary to work over both X.25 and Ethernet if both networks
have TLI interfaces.

The R4 source uses streams pseudotty's as local transport; if your system 
doesn't have them, you can use streams pipes (full duplex pipes, usually
named /dev/spx for the clone device).  I did so on a System V Release 3
machine we have, and it works just fine.  Failing that, you can set up 
local transport as loopback TCP/IP (127.1).  (It is important to get the
local transport running even if you don't have a local server, since the 
daemon & name server are accessed via the local transport mechanism--you
could just butcher the whole works, of course, if you want to give up 
multiple network support.)

If you actually try this and have have some questions, write me.

Randy Brown (uunet!erik!rbrown)