[GRASS5] Raster directory structure, comments

Raymond Burns rayburns at comcast.net
Thu Apr 13 14:23:41 EDT 2006


Hi

I beleive there is an argument against the directory structure
pondered in the "features needed for 6.2" thread.

<mapset>/raster/<mapname>/filetypes

VS

<mapset>/raster/<filetypes>/<mapname>

There does appear to be a limitation on the number of subdirectories
a directory supports, whereas, there appears to be no realistic limit
on the number of files a directory can contain.

No I haven't dug into the code to see where it is but, currently grass
is limited (by the operating system) to 32000 raster maps per mapset
due to some hard limit on my systems which precludes making a
subdirectory in cell_misc for map 32001. At the same time I can add
(touch) additional files in fcell, cellhd, cell, cats ...

I realize 32000 is not a significant limit for most uses of grass
today. As we work with more 3D, volume, animation and modeling it will
probably become more of an issue.

Anyone willing to test this on their platform?  I will gladdly compare
versions and such, ls -l of the mapset directory provides the (32000)
number of links in cell_misc where it fails here, and yes here it is
an nfs mount. 

so for what I'm worth :)  , I'd prefer to side step the limit and go
with

<mapset>/raster/<filetypes>/<mapname>

(including the break up of cell_misc)

allowing a pack/unpack tool to add the creature comforts.


Thanx
  Ray





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