On 7/27/10 6:09 PM, Rob Jarratt wrote:
I would agree that it sounds odd, but the person
telling me knows his stuff
and this has been his experience.
I'm sorry for how terrible this will sound, but I don't know how else
to say it...Where X is concerned, I know my stuff as well, and it really
doesn't sound like your friend does. I mean no disrespect either to you
or to him by that statement. I have an X11 window directly to the right
of the window I'm typing this message in, it's showing colors, and it's
being displayed here from another system on the network. I run like
this all day, every day. I'm not running Exceed, but a different
(current technology) X server, but the concepts and protocol are the same.
I suspect the SHM thing could be why it works on a
real workstation,
Nope. SHM (more properly "MIT-SHM") is only used for images. (XImage
objects in particular, and sometimes pixmaps) Background colors or
drawn objects don't use SHM. It's used where image transfer speed is
important, like video and animations.
or perhaps it is some DEC-specific thing?
Nope. I've run color X terminals (which is essentially what you're
doing with Exceed) from DEC X implementations, and they work fine. This
is where it call came from, after all: DEC was a member of MIT's Project
Athena, where X originated. I've never seen anything DEC specific there
with the exception of DDX (device-dependent) code and their window
manager. The former is almost by definition vendor-specific, and the
latter is too, but perhaps less so depending on your point of view.
Some background: An X client program (which includes your login
window, it's an X client too) initiates a connection to the X server and
does a few things, including optionally making a call to
XGetVisualInfo() to get the list of "visuals" that the server supports.
A "visual" is basically a target display type that specifies the color
depth of the display, and might be something like "monochrome", "8-bit
greyscale", "8-bit pseudocolor", "true color", etc. Most X
servers
support many different visuals simultaneously. The X client then
selects the visual it wants to use. (a note for the pedantic: yes, I've
skipped many Xlib calls and details here for brevity)
It's possible that Exceed does not have any color visuals that the
login window X client supports or wants to select.
Note that I typed "OPTIONALLY makes a call to XGetVisualInfo()" above.
It's possible for an X client to just use the "default" visual, and
that is server-specific, and usually configurable. On most X servers,
the default visual (actually visual "class") is set on the command line
when the server is started. I have no idea of how to set the default
visual for Exceed.
We can drill down a bit further if you'll log into the machine via
Exceed, and run "xdpyinfo" and look at the output. Pay attention to the
visual names and IDs that it reports as being available. Are there any
color visuals present? Also, look at the default visual ID for the
first "screen" entry. See if that visual ID is that of a color visual.
If it isn't, but if there are in fact color visuals present, it's
possible that the login window X client was written to only use the
default visual, which may not be a color visual under Exceed, but might
be a color visual on the workstation. It's also possible that the login
window X client is configurable via its app-defaults file. We can check
on that if you strike out with the visuals described above.
-Dave
--
Dave McGuire
Port Charlotte, FL