HDF5 version 1.5.20 currently under development ================================================================================ INTRODUCTION This document describes the differences between HDF5-1.4.0 and HDF5-1.5-snap0, and contains information on the platforms tested and known problems in HDF5-1.5-snap0. For more details check the HISTORY.txt file in the HDF5 source. The HDF5 documentation can be found on the NCSA ftp server (ftp.ncsa.uiuc.edu) in the directory: /HDF/HDF5/docs/ For more information look at the HDF5 home page at: http://hdf.ncsa.uiuc.edu/HDF5/ If you have any questions or comments, please send them to: hdfhelp@ncsa.uiuc.edu CONTENTS - New Features - Bug Fixes since HDF5-1.4.0 - Platforms Tested - Known Problems Bug Fixes since HDF5-1.4.2 ========================== Library ------- * Fixed bug with contiguous hyperslabs not being detected, causing slower I/O than necessary. * Fixed bug where non-aligned hyperslab I/O on chunked datasets was causing errors during I/O * The RCSID string in H5public.h was causing the C++ compiling problem because when it was included multiple times, C++ did not like multiple definitions of the same static variable. All occurance of RCSID definition are removed since we have not used it consistently before. * Fixed bug with non-zero userblock sizes causing raw data to not write correctly. * Fixed build on Linux systems with --enable-static-exec flag. It now works correctly. * IMPORTANT: Fixed file metadata corruption bug which could cause metadata data loss in certain situations. * The allocation by alignment (H5Pset_alignment) feature code somehow got dropped in some 1.3.x version. Re-implemented it with "new and improved" algorithm. It keeps track of "wasted" file-fragment in the free-list too. * Removed limitation that the data transfer buffer size needed to be set for datasets whose dimensions were too large for the 'all' selection code to handle. Any size dimensioned datasets should be handled correctly now. * Changed behavior of H5Tget_member_type to correctly emulate HDF5 v1.2.x when --enable-hdf5v1_2 configure flag is enabled. * Tweaked a few API functions to use 'size_t' instead of 'unsigned' or 'hsize_t', which may cause errors in some cases. * Fixed a bug of H5pubconf.h causing repeated definitions if it is included more than once. hdf5.h now includes H5public.h which includes H5pubconf.h. Applications should #include hdf5.h which handles multiple inclusion correctly. * Fixed H5FDmpio.h to be C++ friendly by making Parallel HDF5 API's to be external to C++. * Fixed a bug in H5FD_mpio_flush() that might result in negative file seek if both MPIO and Split-file drivers are used together. * Added new parallel hdf5 tests in t_mpi. The new test checks if the filesystem or the MPI-IO can really handle greater than 2GB files. If it fails, it prints information message only without failing the test. * Fixed a bug when reading chunked datasets where the edge of the dataset would be incorrectly detected and generate an assertion failure. * Fixed a bug where reading an entire dataset wasn't being handled optimally when the dataset had unlimited dimensions. Dataset is read in a single low-level I/O now, instead of being broken into separate pieces internally. * Fixed a bug where reading or writing chunked data which needed datatype conversion could result in data values getting corrupted. * Fixed a bug where appending a point selection to the current selection would not actually append the point when there were no points defined currently. * Fixed a bug where 'or'ing a hyperslab with a 'none' selection would fail. Now adds that hyperslab as the first hyperlab in the selection. * Fixed a bug in the 'big' test where quota limits weren't being detected properly if they caused close() to fail. * Fixed a bug in internal B-tree code where a B-tree was not being copied correctly. * Fixed an off-by-one error in H5Sselect_valid when hyperslab selections which would allow hyperslab selections which overlapped the edge of the selection by one element as valid. * Fixed the internal macros used to encode & decode file metadata, to avoid an unaligned access warning on IA64 machines. * Corrected behavior of H5Tinsert to not allow compound datatype fields to be inserted past the end of the datatype. * Retired the DPSS virtual file driver (--with-gridstorage configure option). * Fixed bug where variable-length datatypes for attributes was not working correctly. * Fixed bug where raw data re-allocated from the free-list would sometimes overlap with the metadata accumulator and get corrupted. QAK - 1/23/02 Configuration ------------- * Changed the default value of $NPROCS from 2 to 3 since 3 processes have a much bigger chance catching parallel errors than just 2. * Basic port to Compaq (nee DEC) Alpha OSF 5. * Added --enable-linux-lfs flag to allow more control over whether to enable or disable large file support on Linux. * Require HDF (a.k.a. hdf4) software that consists of a newer version of zlib library which consists of the compress2() function. Versions HDF version 4.1r3 and newer meets this requirement. The compress2 uses a newer compression algorithm used by the HDF5 library. Also, 4.1r3 has an hdp tool that can handle "loops" in Vgroups. * Can use just enable-threadsafe if the C compiler has builtin pthreads support. Tools ----- * Fixed segfault when "-v" flag was used with the h5dumper. * Fixed so that the "-i" flag works correctly with the h5dumper. Documentation ------------- New Features ============ * A helper script called ``h5cc'', which helps compilation of HDF5 programs, is now distributed with HDF5. See the reference manual for information on how to use this feature. * C++ API: - Added two new member functions: Exception::getFuncName() and Exception::getCFuncName() to provide the name of the member function, where an exception is thrown. - IdComponent::operator= becomes a virtual function because DataType, DataSpace, and PropList provide their own implementation. The new operator= functions invoke H5Tcopy, H5Scopy, and H5Pcopy to make a copy of a datatype, dataspace, and property list, respectively. * F90 API: - Added aditional parameter "dims" to the h5dread/h5dwrite and h5aread/h5awrite subroutines. This parameter is 1D array of size 7 and contains the sizes of the data buffer dimensions. * F90 static library is available on Windows platforms. See INSTALL_Windows.txt for details. * F90 APIs are available on HPUX 11.00 and IBM SP platforms. * File sizes greater than 2GB are now supported on Linux systems with version 2.4.x or higher kernels. * Added a global string variable H5_lib_vers_info_g which holds the HDF5 library version information. This can be used to identify an hdf5 library or hdf5 application binary. Also added a verification of the consistency between H5_lib_vers_info_g and other version information in the source code. * H5 <-> GIF convertor has been added. This is available under tools/gifconv. The convertor supports the ability to create animated gifs as well. * Parallel HDF5 now runs on the HP V2500 and HP N4000 machines. * Verified correct operation of library on Solaris 2.8 in both 64-bit and 32-bit compilation modes. See INSTALL document for instructions on compiling the distribution with 64-bit support. * Modified the Pablo build procedure to permit building of the instrumented library to link either with the Trace libraries as before or with the Pablo Performance Caputure Facility. * Improved regular hyperslab I/O by about a factor of 6 or so. * Added two simple parallel performance tests as mpi-perf.c (MPI performance) and perf.c (PHDF5 performance) in testpar. * Added a parallel HDF5 example examples/ph5example.c to illustrate the basic way of using parallel HDF5. * Added a new public macro, H5_VERS_INFO, which is a string holding the HDF5 library version information. This string is also compiled into all HDF5 binary code which helps to identify the version information of the binary code. One may use the Unix strings command on the binary file and looks for the pattern "HDF5 library version". * Added new checking in H5check_version() to verify the five HDF5 version information macros (H5_VERS_MAJOR, H5_VERS_MINOR, H5_VERS_RELEASE, H5_VERS_SUBRELEASE and H5_VERS_INFO) are consistent. * Added perform programs to test the HDF5 library performance. Programs are installed in directory perform/. * The H5Pset_fapl_split() accepts raw and meta file names similar to the syntax of H5Pset_fapl_multi() in addition to what it used to accept. * Added a new test to verify the information provided by the configure command. * As part of the transition to using generic properties everywhere, the parameter of H5Pcreate changed from H5P_class_t to hid_t, as well the return type of H5Pget_class changed from H5P_class_t to hid_t. Further changes are still necessary and will be documented here as they are made. * Improved performance of single, contiguous hyperslabs when reading or writing. * Improved performance of non-contiguous hyperslabs (built up with several hyperslab selection calls). * Removed H5P(get|set)_hyper_cache API function, since the property is no longer used. * Added a new file access property, file close degree, to control file close behavior. It has four values, H5F_CLOSE_WEAK, H5F_CLOSE_SEMI, H5F_CLOSE_STRONG, and H5F_CLOSE_DEFAULT. Two correspont functions H5Pset_fclose_degree and H5Pget_fclose_degree are also provided. Two new functions H5Fget_obj_count and H5Fget_obj_ids are offerted to assist this new feature. For full details, please refer to the reference manual under the description of H5Fcreate, H5Fopen, H5Fclose and the functions mentioned above. * Changed internal error handling macros to reduce code size of library by about 10-20%. * Added H5Rget_obj_type() API function, which performs the same functionality as H5Rget_object_type(), but requires the reference type as a parameter in order to correctly handle dataset region references. Moved H5Rget_object_type() to be only compiled into the library when v1.4 compatibility is enabled. * Parallel HDF5 is now supported on HP-UX 11.00 platforms. * Added support to read/write portions of chunks directly, if they are uncompressed and too large to cache. This should speed up I/O on chunked datasets for a few more cases. -QAK, 1/31/02 * Added new "H5Sget_select_type" API function to determine which type of selection is defined for a dataspace ("all", "none", "hyperslab" or "point"). -QAK, 2/7/02 Platforms Tested ================ AIX 4.3.3.0 (IBM SP powerpc) mpcc_r 3.6.6 Cray T3E sn6711 2.0.5.45 Cray Standard C Version 6.4.0.0 Cray Fortran Version 3.4.0.2 Cray SV1 sn9605 10.0.0.7 Cray Standard C Version 6.4.0.0 Cray Fortran Version 3.4.0.2 FreeBSD 4.3 gcc 2.95.2 g++ 2.95.2 HP-UX B.10.20 HP C HP92453-01 A.10.32.30 HP-UX B.11.00 HP C HP92453-01 A.11.00.13 HP C HP92453-01 A.11.01.20 IRIX 6.5 MIPSpro cc 7.30 IRIX64 6.5 (64 & n32) MIPSpro cc 7.3.1m mpt.1.4.0.2 mpich-1.2.1 Linux 2.4.4 gcc-2.95.3 g++ 2.95.3 Linux 2.2.16-3smp gcc-2.95.2 g++ 2.95.2 pgf90 3.1-3 OSF1 V4.0 DEC-V5.2-040 Digital Fortran 90 V4.1-270 SunOS 5.6 WorkShop Compilers 5.0 98/12/15 C 5.0 (Solaris 2.6) WorkShop Compilers 5.0 99/10/25 Fortran 90 2.0 Patch 107356-04 Workshop Compilers 5.0 98/12/15 C++ 5.0 SunOS 5.7 WorkShop Compilers 5.0 98/12/15 C 5.0 (Solaris 2.7) WorkShop Compilers 5.0 99/10/25 Fortran 90 2.0 Patch 107356-04 Workshop Compilers 5.0 98/12/15 C++ 5.0 TFLOPS r1.0.4 v4.0 mpich-1.2.1 with local changes Windows NT4.0, 2000 (NT5.0) MSVC++ 6.0 Windows 98 MSVC++ 6.0 Known Problems ============== * Datasets or attributes which have a variable-length string datatype are not printing correctly with h5dump and h5ls. * DLLs do not work on Windows 98 * RELEASE DLLs will fail on some tests on Windows 2000 with Microsoft visual studio 6.0 due to memory allocation problems caused by compiler. Users are encouraged to go to microsoft site to find and install visual studio 6.0 service pack 5. After that, release dlls will work. * The stream-vfd test uses ip port 10007 for testing. If another application is already using that port address, the test will hang indefinitely and has to be terminated by the kill command. To try the test again, change the port address in test/stream_test.c to one not being used in the host. * The --enable-static-exec configure flag fails to compile for Solaris platforms. This is due to the fact that not all of the system libraries on Solaris are available in a static format. The --enable-static-exec configure flag also fails to correctly compile on IBM SP2 platform for the serial mode. The parallel mode works fine with this option. It is suggested that you don't use this option on these platforms during configuration. * With the gcc 2.95.2 compiler, HDF 5 uses the `-ansi' flag during compilation. The ANSI version of the compiler complains about not being able to handle the `long long' datatype with the warning: warning: ANSI C does not support `long long' This warning is innocuous and can be safely ignored. * SunOS 5.6 with C WorkShop Compilers 4.2: Hyperslab selections will fail if library is compiled using optimization of any level. * h5toh4 converter fails two cases (tstr.h5 and tmany.h5) for release dll version on windows 2000 and NT. The reason is possibly due to windows NT DLL convention on freeing memory. It seems that memory cannot be free across library or DLL. It is still under investigated. * The Stream VFD was not tested yet under Windows. It is not supported in the TFLOPS machine. * Shared library option is broken for IBM SP and some Origin 2000 platforms. One needs to run ./configure with '--disable-shared' * The ./dsets tests failed in the TFLOPS machine if the test program, dsets.c, is compiled with the -O option. The hdf5 library still works correctly with the -O option. The test program works fine if it is compiled with -O1 or -O0. Only -O (same as -O2) causes the test program to fail. * Certain platforms give false negatives when testing h5ls: - Solaris x86 2.5.1, Cray T3E and Cray J90 give errors during testing when displaying object references in certain files. These are benign differences due to the difference in sizes of the objects created on those platforms. h5ls appears to be dumping object references correctly. - Cray J90 (and Cray T3E?) give errors during testing when displaying some floating-point values. These are benign differences due to the different precision in the values displayed and h5ls appears to be dumping floating-point numbers correctly. * Before building HDF5 F90 Library from source on Crays (T3E and J90) replace H5Aff.f90, H5Dff.f90 and H5Pff.f90 files in the fortran/src subdirectory in the top level directory with the Cray-specific files from the site: ftp://hdf.ncsa.uiuc.edu/pub/ougoing/hdf5/hdf5-1.4.0-beta/F90_source_for_Crays