-
2008.08.19 16:05 "Re: [Tiff] Regarding DICONDE and its Specification", by Bob Friesenhahn
- 2008.08.20 12:37 "Re: [Tiff] Regarding DICONDE and its Specification", by Harsha
- 2008.08.20 14:03 "Re: [Tiff] Regarding DICONDE and its Specification", by Gene Amtower
-
2008.08.22 15:21 "Re: [Tiff] creating sparse files......", by Toby Thain
-
2008.08.22 08:56 "[Tiff] creating sparse files......", by Rogier Wolff
- 2008.08.22 13:11 "Re: [Tiff] creating sparse files......", by Toby Thain
-
2008.08.22 14:44 "Re: [Tiff] creating sparse files......", by Bob Friesenhahn
-
2008.08.22 16:27 "Re: [Tiff] creating sparse files......", by Rogier Wolff
-
2008.08.22 16:40 "Re: [Tiff] creating sparse files......", by Bob Friesenhahn
-
2008.08.22 16:52 "Re: [Tiff] creating sparse files......", by Rogier Wolff
-
2008.08.22 18:11 "Re: [Tiff] creating sparse files......", by Bob Friesenhahn
- 2008.08.22 20:02 "Re: [Tiff] creating sparse files......", by Phillip Crews
- 2008.08.23 15:08 "Re: [Tiff] creating sparse files......", by Rogier Wolff
-
2008.08.22 18:11 "Re: [Tiff] creating sparse files......", by Bob Friesenhahn
-
2008.08.22 16:52 "Re: [Tiff] creating sparse files......", by Rogier Wolff
-
2008.08.22 16:40 "Re: [Tiff] creating sparse files......", by Bob Friesenhahn
-
2008.08.22 16:27 "Re: [Tiff] creating sparse files......", by Rogier Wolff
- 2008.08.25 06:28 "Re: [Tiff] creating sparse files......", by Andrey Kiselev
- 2008.08.25 09:37 "Re: [Tiff] creating sparse files......", by John
- 2008.08.26 13:14 "Re: [Tiff] creating sparse files......", by Edward Lam
- 2008.08.23 18:49 "Re: [Tiff] creating sparse files......", by Rogier Wolff
-
2008.08.22 08:56 "[Tiff] creating sparse files......", by Rogier Wolff
2008.08.22 14:44 "Re: [Tiff] creating sparse files......", by Bob Friesenhahn
I'm stitching kind of large panoramas. This results in big
intermediate files. On my last run, which took overnight to stitch, 42 Gb of free disk space would be enough. Wrong! I thought I
got over thrity files of over 1.2Gbytes, filling up the disk.
It turns out that most of the files contain lots of zeroes. On Unix be stored effciently by not issueing a "write" with a buffer this can
full of zeroes, but by seeking over the area. The operating system as if the area was filled with zeroes. will act
This is an interesting issue. While holey files seem like a panacea, there can be some drawbacks. They are best for files which are written just once (like core files) and not so good for files which are expected to be updated in place. For files which are updated in place, the updated hole is quite likely to increase disk fragmentation since now it takes more space and the space will need to be from some other place on disk. Fragmentation behavior is quite filesystem dependent.
It is worth considering enabling filesystem compression, or using whole-file compression. Perhaps even just enabling normal TIFF compression (e.g. LZW) is sufficient to eliminate the long spans of zeros.
Bob
======================================
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/