James Holton schrieb:
...
> In any case, I think it is important to remember that there are good
> reasons for leaving image file formats uncompressed. Probably the most
> important is the activation barrier to new authors writing new programs
> that read them. "fread()" is one thing, but finding the third-party
> code for a particular compression algorithm, navigating a CVS repository
> and linking to a library are quite another! This is actually quite a
> leap for those of us who never had any formal training in computer
> science. Personally, I still haven't figured out how to read pck
> images, as it is much easier to write "jiffy" programs for uncompressed
pck code can be found at http://www.ccp4.ac.uk/dist/lib/src/pack_c.c
CBF code is at http://www.bernstein-plus-sons.com/software/CBF/
Both are under GPL
> data. For example, if all you want to do is extract a group of pixels
> (such as a spot), then you have to decompress the whole image! In
> computer speak: fseek() is rendered useless by compression. This could
> be why Mar opted not to use the pck compression for their newer
> CCD-based detectors?
thinking about the many GB written daily at a synchrotron beamline, I
wish they had !
>
> That said, compressed file systems do appear particularly attractive if
> space is limiting. Apparently HFS can do it, but what about other
> operating systems? Does anyone have experience with a Linux file system
> that both supports compression and doesn't get corrupted easily?
>
One possibility in Linux is ZFS over FUSE; this has a large number of
advantages over other filesystems (except Btrfs) - see
http://www.linux-magazine.com/w3/issue/103/ZFS.pdf . The article
explains installation for Ubuntu. I must admit that I did not try it so far.
The alternative would be Btrfs, see
http://www.h-online.com/open/The-Btrfs-file-system--/features/113738 .
This is available for latest Fedora and Ubuntu, is part of the recently
released 2.6.31 kernel
(http://www.h-online.com/open/Kernel-Log-2-6-31-Tracking--/features/113671),
and will therefore in the future be available in all distros.
best,
Kay
--
Kay Diederichs http://strucbio.biologie.uni-konstanz.de
email: [log in to unmask] Tel +49 7531 88 4049 Fax 3183
Fachbereich Biologie, Universitaet Konstanz, Box M647, D-78457 Konstanz
|