FOLLLOWUP TO: X11R4 on DEC 5000 Ultrix 4.x

[Steve Schoch]

In article <1991May8.235652.2246 at crl.dec.com>, jg at crl.dec.com (Jim Gettys) writes:
|> The biggest reason for vendors to convert to R4 servers are two things:
|> 1) better memory utilization
|> 2) higher performance, particularly for windowing operations.
|> Many/most of 2) were implemented by Digital, and the results given to
|> MIT for R4, so it has been less pressing for us to convert than most
|> manufacturers.

There are a couple of other, more obscure reasons:

1) The R4 server handles new connections differently.  Try this on your
workstation:  telnet <your workstation> 6000
If you are running R4, you telnet will connect and your server will go
about its business of dealing with other clients.  If your are running
R3 (e.g. DECwindows) your server will freeze for about 60 seconds.  The
reason for this can be seen by looking in the routine EstablishNewConnections
in server/os/4.2bsd and comparing R3 against R4.  The scary thing is that
anyone on the network can freeze your server this way whether they are
authorized to connect to your display or not.

2) The R4 server has a way of giving access to your server on a per-
client basis in addition to the per-machine method of R3.  If you do
all of your work on your workstation you probably don't care about this,
but if you run clients from a "public" machine it is nice that other
users on that machine can't do nasty things to your display (e.g. "bounce").

I am anxiously waiting for DEC to release a DECwindows that does these
things.

	Steve