2017-10-02 18:56 GMT+02:00 Barbara Jones <bljo...@hdfgroup.org>: > Hi Markus, > > > > Just letting you know that bug HDFFV-10300 was entered for this issue. >5 > We will investigate it and get back to you on this.
Sorry to jump in, but this time I have to ask: Is the bug tracker where these "HDFFV" bugs are filed available somewhere? I know I've seen some discussions in the past about opening up the HDF5 development process. Has there been any movements on this yet? I'm quite interested in following the triaging/work/discussions around this bug, but if there's no bug tracker where I can subscribe to the bug activity, like I can with most other open source projects, I don't see how I can do that. Whenever one of these mail threads end with a "HDFFV-XXX has been entered", it's as if the issue disappears into a black hole, only to come out again when the problem is already solved. I find that sad, because no-one outside of the HDF5 Group can really learn anything from this :/ Elvis > > > > Thanks! > > -Barbara > > h...@hdfgroup.org > > > > > > From: Hdf-forum [mailto:hdf-forum-boun...@lists.hdfgroup.org] On Behalf Of > Krug, Markus > Sent: Tuesday, September 05, 2017 2:57 AM > To: HDF Users Discussion List > Subject: [Hdf-forum] HDF lib incompatible with HDF file spec? > > > > Dear all, > > > > I just came around an interesting issue. > > I implemented the writing of HDF files on an embedded system. The amount of > functionality I implemented is significant less than the HDF lib offers. So > it is just tailored to my needs. I implemented everything on base of the HDF > 3.0 file spec. One point of my tailoring was to optimize the file size. > Therefore, I write every internal block in the HDF files aligned > byte-by-byte to the next – or padded to the address alignment if it is > requested by the HDF file specification. The HDF files generated by HDFview > or Matlab have plenty of space in-between the internal blocks. Sometimes a > few hundred bytes. As far as I read from the HDF file specification this > ‘extended padding’ is not defined at all – not even recommended. > > However, this ‘extended padding’ that is performed by the HDF lib leads to a > behavior that I would consider as an incompatibility to itself. To > demonstrate this I attached two HDF files to this email. The first > (sizeoptimized.h5) is generated by my embedded software and is optimized > concerning the file size. It contains three compounds with each of them has > 2 elements. You should be able to open that file in HDFview or similar tools > and read all its contents. > > The second file (sizeoptimizedextended.h5) is generated by HDFview by adding > a fourth compound after the sizeoptimized.h5 file was opened in HDFview. You > can see that the file is partly corrupted. The reason for this is that > HDFview (and therefore the HDF lib I guess) is not really taking care about > the position of the internal blocks of a file that it is writing to. It > seems to me it has some internal mapping of those blocks. This mapping gets > applied even if it will collide, and therefore corrupt, the existing blocks. > > If my observation is correct I think the HDF lib will need a bugfix or the > HDF file spec will need a description of how the internal blocks are allowed > to be positioned within a HDF file. > > I forgot to mention that I tried to use the HDF lib sources and compile it > to my system. However, I quit after a couple of days because the way the > sources are written are not suitable at all to adopt them to an embedded > system that runs a simplified file system and a real-time operating system – > and all of it has to fit into a few hundred kilobytes. > > > > Can anyone comment on my observation? > > > > > > Best Regards > > Markus > > > _______________________________________________ > Hdf-forum is for HDF software users discussion. > Hdf-forum@lists.hdfgroup.org > http://lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org > Twitter: https://twitter.com/hdf5 _______________________________________________ Hdf-forum is for HDF software users discussion. Hdf-forum@lists.hdfgroup.org http://lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org Twitter: https://twitter.com/hdf5
