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Diffstat (limited to 'RELEASE')
| -rw-r--r-- | RELEASE | 67 |
1 files changed, 67 insertions, 0 deletions
@@ -29,6 +29,7 @@ If you have any questions or comments, please send them to: CONTENTS - New features +- New h4toh5 utility - Bug fixes since HDF5-1.2.0 - Platforms Tested - Known Problems @@ -53,7 +54,73 @@ New features * Added 'query' function to VFL drivers. Also added 'type' parameter to VFL 'read' & 'write' calls, so they are aware of the type of data being accessed in the file. Updated the VFL document also. + * A new h4toh5 uitlity, to convert HDF4 files to analogous + HDF5 files. +Release Notes for h4toh5 beta +============================= + +The h4toh5 utility converts an HDF4 file to an HDF5 file. +See the document, "Mapping HDF4 Objects to HDF5 Objects", +http://hdf.ncsa.uiuc.edu/HDF5/papers/H4-H5MappingGuidelines.pdf + +Known Limitations of the h4toh5 beta release +============================================= + +1. Error handling + +Error reporting is minimal. + +2. String datatype + +HDF4 has no 'string' type. String valued data are usually defined +as an array of 'char' in HDF4. The h4toh5 utility will generally +map these to HDF5 'String' types rather than array of char, with +the following additional rules: + + * For the data of HDF4 SDS, image, and palette, if the data is + declared 'DFNT_CHAR8' it will be assumed to be integer and + will be an H5T_INTEGER type. + * For attributes of any HDF4 object, data of type 'DFNT_CHAR8' + will be converted to an HDF5 'H5T_STRING' type. + * For Vdata of HDF4, it is difficult to determine whether data + of type 'DFNT_CHAR8' is intended to be bytes or charaters. + The h4toh5 utility will consider them as C character, and + will convert them to an HDF5 'H5T_STRING' type. + + +3. Compression, Chunking and External storage + +Chunking is supported, but compression and external storage is +not. + +An HDF4 object that uses chunking will be converted to an HDF5 +file with analogous chunked storage. + +An HDF4 object that uses compression will be converted to an +uncompressed HDF5 object. + +An HDF4 object that uses external storage will be converted to an +an HDF5 object without external storage. + +4. Memory use + +The beta version of the h4toh5 utility copies data from HDF4 +objects in a single read followed by a single write to the +HDF5 object. For large objects, this requires a very large +amount of memory, which may be extremely slow or fail on +some platforms. + +Note that a dataset that has only been partly written will +be read completely, including uninitialized data, and all the +data will be written to the HDF5 object. + +5. Platforms + +The h4toh5 utility requires HDF5.1.4. + +The beta h4toh5 utility has been tested on Solaris 2.6, Solaris 2.5, +Irix 6.5, HPUX 11.0, DEC Unix, FreeBSD, and Windows 2000. Bug fixes since HDF5-1.2.0 ========================== |