can not start monitor

Justin Hickey jhickey at
Wed Oct 1 11:44:39 EDT 1997

Hi Rainer

On Sep 30,  6:44pm, Rainer Bärs wrote:
> Subject: can not start monitor
> I just recompiled grass for my DEC Alphastation and for my SGI INDY. After
> getting the usual (?) compilation errors, I finally got everything up and
> running. Or so I thought!
> When I say 'd.mon start=x0' to my Alphastation it says:
> Graphics driver [x0] started
> can't read index!
> ERROR eof from graphics driver.
> Problem selecting x0. Will try once more
> Please start graphics monitor <x0>.
> Error - Graphics monitor <x0> not running!

Is your alphastation a 64-bit system? If so then I know the answer to your
problem (I had the same problem with our 64 bit version on our SGI). I include
here my notes on the problem and how I fixed it.

The problem turned out to be that to process the fonts for the graphics driver,
they were reading from a file a certain number of bytes. The calculation of
this number of bytes was based on the size of a pointer (8 for 64 bit systems)
when in reality, the number of bytes available for reading was based on 4 (the
size of pointers on 32 bit systems). It actually has nothing to do with the
size of pointers, thus the calculation was too large and the read command was
trying to read more bytes than were available. The problem was fixed by
changing line 43 of the file $GIS/src/display/devices/XDRIVER/lib/font.c to the
	size = nchars * 4;

Hope this helps.


Jazzman (a.k.a. Justin Hickey)  e-mail: jhickey at
High Performance Computing Center
National Electronics and Computer Technology Center (NECTEC)
Bangkok, Thailand
People who think they know everything are very irritating to those
of us who do.  ---Anonymous

Jazz and Trek Rule!!!

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