HDF Newsletter #7 March 2, 1993 CONTENTS 1. HDF3.2 Release 4 2. XDataSlice now takes new number types 3. HDF3.3 Alpha release 4 4. HDF 3.2 is slow on the Mac HDF3.2 Release 4 ---------------- HDF 3.2 release 4 merges the source code of 3.2 release 3 and the patch files which contain the bug fixes since release 3 has been officailly released. See CODECHANGES in HDF/HDF3.2r4/unpacked/ for details. In HDF3.2 release 1, 2 and 3 there is a bug in writing data label, unit and format. When writing an SDS, if only DFSDsetdatastrs() was called and no DFSDsetdimstrs() was called the bug will appear in the hdf file. If none of DFSDsetdimstrs() and DFSDsetdatastrs() was called, or both of them were called, or only DFSDsetdimstrs() was called, there will be no such bug in the hdf file. The bug might cause segmentation fault on SGI and other platforms when DFSDgetdims or DFSDgetdata is called to read in that SDS. The bug was fixed and the fix was included in the patch file patch01 in HDF/HDF3.2r3/patches/. Also, a patched dfsd.c was in HDF/HDF3.2r3/patches/patchedsrc/src/. Besides, there were other bug fixes in dfan.c and utility programs in patch01 and patch02. Since some users downloaded HDF programs without downloading the patches at the same time, we feel need to update HDF on ftp with the patch files merged into the code to avoid users' writing wrong hdf files. If you haven't patched your HDF3.2r3 using the patch files please download 3.2r4 and reinstall your HDF library. The executable code on NCSA platforms: CRAY-2, CRAY-YMP, CONVEX and REL was updated on Feb. 24 and 25. If you have any question please contact sxu@ncsa.uiuc.edu. If you have used HDF3.2 release 1, 2 or 3 to write SDSs with the bugs mentioned above, you need to rewrite the hdf file. We are trying to make a utility which will search for the bug through an hdf file and rewrite the SDS data strings. We will send another notice when the utility is ready. We are very sorry for having not caught the bug and fixed it earlier. XDataSlice now takes new number types ------------------------------------- Gilles Bourhis, visitor from France, has upgraded NCSA XDataSlice to accept all number types supported by HDF3.2. The new release, XDataSlice version 2.2 is on NCSA ftp server (ftp.ncsa.uiuc.edu), in subdirectory: UNIX/XDataSlice/XDS2.2 HDF3.3 Alpha release 4 ---------------------- HDF 3.3 alpha release 4 has been installed on the NCSA ftp server. This alpha release contains most of the new features that will be available in the full release of HDF 3.3. (As soon as all features are available, we will distribute a beta release.) HDF version 3.3 release 4 supplies the following features that are not available in HDF 3.2: o Support for reading and writing JPEG compressed 24-bit and 8-bit raster images o A utility for ingesting JPEG images into an HDF file. o Support for reading and writing Little-Endian (PC Native) mode files on all platforms in Vdatas and SDSs. o Improved I/O performance on Cray and VMS platforms. o Support for the netCDF interface and data model. It is now possible, via the netCDF interface to do the following: * read XDR-based (Unidata format) netCDF file * read and write HDF-based netCDFs to HDF files * read HDF SDSs. o An SDS interface with the following features: * support for simultaneous access to more than one file (uses file handles) * support for simultaneous access to more than one HDF object (uses object handles) * support for reading and writing hyperslabs at random places in an SDS. * support for an unlimited dimension in an SDS. * faster access to files with many data sets * faster access on Crays * transparent access to netCDFs that conform to the SDS data model. Other features that are planned for HDF 3.3: o The ability to store SDS dimension scales of a different data type than that of the corresponding data. o The ability to store a palette with an SDS. o The ability to subsample data in an SDS. HDF3.3 Alpha releases 1, 2 and 4 are on NCSA ftp server in subdirectory: HDF/HDF3.3-ALPHA/ The README file in that directory lists the features for each release and the new functions in each interfaces. This is an "alpha" release and is bound to have bugs. You can help us a great deal by reporting any problems you have with the library, as well as any other suggestions or comments. HDF 3.2 is slow on the Mac -------------------------- We have had reports that HDF 3.2 is running much slower on the Mac than did earlier versions of HDF. We are trying to track down the reasons for this but have not yet been able to find them. If you have any ideas, please share them with us.