r.surf.contour bogs down

[Bob Harrington]

I'm running GRASS 4.1 on an DEC 3000 with OSF 1.

I've got several digitized and rasterized contour maps that I'd like
to paste together into a regional DEM.  I pasted the quadrangles together with
r.patch, and now am running 'r.surf.contour -f' to interpolate values for
the areas between the contours.  The region is large -- about 12 million 
cells.

r.surf.contour indicated that it finished about 10% of the job in the
first hour, but here it is two days later and it indicates that it's
only done 24% of the job -- only 1% progress last night.  Why has it 
slowed down so much?  

I figured that running r.patch before r.surf.contour would do a smoother
job along the edges of the quadrangles, but I suppose I could reverse
the order of those operations.  Any insights?

Bob Harrington
bobh at hwr.arizona.edu
Hydrology and Water Resources, University of Arizona, Tucson, Arizona