path: root/RELEASE

Release information for hdf5-1.0.23a
------------------------------------
		    CHANGES SINCE THE SECOND ALPHA

* Strided hyperslab selections in dataspaces now working.

* The compression API has been replaced with a more general filter
  API.  See doc/html/Filters.html for details.

		    CHANGES SINCE THE FIRST ALPHA

* Two of the packages have been renamed.  The data space API has been
  renamed from `H5P' to `H5S' and the property list (template) API has 
  been renamed from `H5C' to `H5P'.

* The new attribute API `H5A' has been added.  An attribute is a small 
  dataset which can be attached to some other object (for instance, a
  4x4 transformation matrix attached to a 3-dimensional dataset, or an 
  English abstract attached to a group).

* The error handling API `H5E' has been completed.  By default, when an
  API function returns failure an error stack is displayed on the
  standard error stream.  The H5Eset_auto() controls the automatic
  printing and H5E_BEGIN_TRY/H5E_END_TRY macros can temporarily
  disable the automatic error printing.

* Support for large files and datasets (>2GB) has been added.  There
  is an html document that describes how it works.  Some of the types
  for function arguments have changed to support this: all arguments
  pertaining to sizes of memory objects are `size_t' and all arguments 
  pertaining to file sizes are `hsize_t'.

* More data type conversions have been added although none of them are
  fine tuned for performance.  There are new converters from integer
  to integer and float to float, but not between integers and floating
  points.  A bug has been fixed in the converter between compound
  types.

* The numbered types have been removed from the API: int8, uint8,
  int16, uint16, int32, uint32, int64, uint64, float32, and float64.
  Use standard C types instead.  Similarly, the numbered types were
  removed from the H5T_NATIVE_* architecture; use unnumbered types
  which correspond to the standard C types like H5T_NATIVE_INT.

* More debugging support was added.  If tracing is enabled at
  configuration time (the default) and the HDF5_TRACE environment
  variable is set to a file descriptor then all API calls will emit
  the function name, argument names and values, and return value on
  that file number.  There is an html document that describes this.
  If appropriate debugging options are enabled at configuration time,
  some packages will display performance information on stderr.

* Data types can be stored in the file as independent objects and
  multiple datasets can share a data type.

* The raw data I/O stream has been implemented and the application can 
  control meta and raw data caches, so I/O performance should be
  improved from the first alpha release.

* Group and attribute query functions have been implemented so it is
  now possible to find out the contents of a file with no prior
  knowledge.

* External raw data storage allows datasets to be written by other
  applications or I/O libraries and described and accessed through
  HDF5.

* Hard and soft (symbolic) links are implemented which allow groups to 
  share objects. Dangling and recursive symbolic links are supported.

* User-defined data compression is implemented although we may
  generalize the interface to allow arbitrary user-defined filters
  which can be used for compression, checksums, encryption,
  performance monitoring, etc.  The publicly-available `deflate'
  method is predefined if the GNU libz.a can be found at configuration 
  time.

* The configuration scripts have been modified to make it easier to
  build debugging vs. production versions of the library.

* The library automatically checks that the application was compiled
  with the correct version of header files.


		    Parallel HDF5 Changes

* Parallel support for fixed dimension datasets with contiguous or
  chunked storages.  Also, support unlimited dimension datasets which
  must use chunk storage.  No parallel support for compressed datasets.

* Collective data transfer for H5Dread/H5Dwrite.  Collective access
  support for datasets with contiguous storage only, thus only fixed
  dimension datasets for now.

* H5Pset_mpi and H5Pget_mpi no longer have the access_mode
  argument.  It is taken over by the data-transfer property list
  of H5Dread/H5Dwrite.

* New functions H5Pset_xfer and H5Pget_xfer to handle the
  specification of independent or collective data transfer_mode
  in the dataset transfer properties list.  The properties
  list can be used to specify data transfer mode in the H5Dwrite
  and H5Dread function calls.

* Added parallel support for datasets with chunked storage layout.
  When a dataset is extend in a PHDF5 file, all processes that open
  the file must collectively call H5Dextend with identical new dimension
  sizes.


			LIST OF API FUNCTIONS

The following functions are implemented. Errors are returned if an
attempt is made to use some feature which is not implemented and
printing the error stack will show `not implemented yet'.

Library
   H5check		- check that lib version matches header version
   H5open		- initialize library (happens automatically)
   H5close		- shut down the library (happens automatically)
   H5dont_atexit	- don't call H5close on exit
   H5version		- retrieve library version info
   H5version_check	- check for specific library version

Property Lists
   H5Pclose		- release template resources
   H5Pcopy		- copy a template
   H5Pcreate		- create a new template
   H5Pget_chunk		- get chunked storage properties
   H5Pset_chunk		- set chunked storage properties
   H5Pget_class		- get template class
   H5Pget_istore_k	- get chunked storage properties
   H5Pset_istore_k	- set chunked storage properties
   H5Pget_layout	- get raw data layout class
   H5Pset_layout	- set raw data layout class
   H5Pget_sizes		- get address and size sizes
   H5Pset_sizes		- set address and size sizes
   H5Pget_sym_k		- get symbol table storage properties
   H5Pset_sym_k		- set symbol table storage properties
   H5Pget_userblock	- get user-block size
   H5Pset_userblock	- set user-block size
   H5Pget_version	- get file version numbers
   H5Pget_alignment	- get data alignment properties
   H5Pset_alignment	- set data alignment properties
   H5Pget_external_count- get count of external data files
   H5Pget_external	- get information about an external data file
   H5Pset_external	- add a new external data file to the list
   H5Pget_driver	- get low-level file driver class
   H5Pget_stdio		- get properties for stdio low-level driver
   H5Pset_stdio		- set properties for stdio low-level driver
   H5Pget_sec2		- get properties for sec2 low-level driver
   H5Pset_sec2		- set properties for sec2 low-level driver
   H5Pget_core		- get properties for core low-level driver
   H5Pset_core		- set properties for core low-level driver
   H5Pget_split		- get properties for split low-level driver
   H5Pset_split		- set properties for split low-level driver
   H5P_get_family	- get properties for family low-level driver
   H5P_set_family	- set properties for family low-level driver
   H5Pget_cache		- get meta- and raw-data caching properties
   H5Pset_cache		- set meta- and raw-data caching properties
   H5Pget_buffer	- get raw-data I/O pipe buffer properties
   H5Pset_buffer	- set raw-data I/O pipe buffer properties
   H5Pget_preserve	- get type conversion preservation properties
   H5Pset_preserve	- set type conversion preservation properties
   H5Pget_compression	- get raw data compression properties
   H5Pset_compression	- set raw data compression properties
   H5Pget_deflate	- get deflate compression properties
   H5Pset_deflate	- set deflate compression properties
   H5Pget_mpi		- get MPI-IO properties
   H5Pset_mpi		- set MPI-IO properties
   H5Pget_xfer		- get data transfer properties
   H5Pset_xfer		- set data transfer properties

Datasets
   H5Dclose		- release dataset resources
   H5Dcreate		- create a new dataset
   H5Dget_space		- get data space
   H5Dget_type		- get data type
   H5Dget_create_plist	- get dataset creation properties
   H5Dopen		- open an existing dataset
   H5Dread		- read raw data
   H5Dwrite		- write raw data
   H5Dextend		- extend a dataset

Attributes
   H5Acreate	- create a new attribute
   H5Aopen_name	- open an attribute by name
   H5Aopen_idx	- open an attribute by number
   H5Awrite		- write values into an attribute
   H5Aread		- read values from an attribute
   H5Aget_space	- get attribute data space
   H5Aget_type	- get attribute data type
   H5Aget_name	- get attribute name
   H5Anum_attrs	- return the number of attributes for an object
   H5Aiterate	- iterate over an object's attributes
   H5Adelete	- delete an attribute
   H5Aclose		- close an attribute

Errors
   H5Eclear		- clear the error stack
   H5Eprint		- print an error stack
   H5Eget_auto	- get automatic error reporting settings
   H5Eset_auto	- set automatic error reporting
   H5Ewalk		- iterate over the error stack
   H5Ewalk_cb	- the default error stack iterator function
   H5Eget_major	- get the message for the major error number
   H5Eget_minor	- get the message for the minor error number

Files
   H5Fclose		    - close a file and release resources
   H5Fcreate		- create a new file
   H5Fget_create_template- get file creation property list
   H5Fget_access_template- get file access property list
   H5Fis_hdf5		- determine if a file is an hdf5 file
   H5Fopen		    - open an existing file

Groups
   H5Gclose		- close a group and release resources
   H5Gcreate    - create a new group
   H5Gopen		- open an existing group
   H5Gpop		- pop a group from the cwg stack
   H5Gpush		- push a group onto the cwg stack
   H5Gset		- set the current working group (cwg)
   H5Giterate   - iterate over the contents of a group
   H5Gmove		- change the name of some object
   H5Glink		- create a hard or soft link to an object
   H5Gunlink    - break the link between a name and an object
   H5Gstat		- get information about a group entry
   H5Gget_linkval	- get the value of a soft link

Dataspaces
   H5Sclose		        - release dataspace
   H5Screate	        - create a new dataspace
   H5Screate_simple	    - create a new simple dataspace
   H5Sextent_dims		- get dataspace size
   H5Sselect_hyperslab	- set hyperslab dataspace selection
   H5Sselect_elements   - set element sequence dataspace selection
   H5Sextent_ndims		- get dataspace dimensionality
   H5Sextent_npoints	- get number of points in extent of dataspace
   H5Sselect_npoints	- get number of selected points in dataspace
   H5Sis_simple		    - determine if dataspace is simple
   H5Sset_extent_simple	- set simple dataspace dimensionality and size
   H5Scopy		        - copy a dataspace

Datatypes
   H5Tclose		- release data type resources
   H5Topen		- open a named data type
   H5Tcommit		- name a data type
   H5Tcommitted		- determine if a type is named
   H5Tcopy		- copy a data type
   H5Tcreate		- create a new data type
   H5Tequal		- compare two data types
   H5Tfind		- find a data type conversion function
   H5Tconvert		- convert data from one type to another
   H5Tget_class		- get data type class
   H5Tget_cset		- get character set
   H5Tget_ebias		- get exponent bias
   H5Tget_fields	- get floating point fields
   H5Tget_inpad		- get inter-field padding
   H5Tget_member_dims	- get struct member dimensions
   H5Tget_member_name	- get struct member name
   H5Tget_member_offset	- get struct member byte offset
   H5Tget_member_type	- get struct member type
   H5Tget_nmembers	- get number of struct members
   H5Tget_norm		- get floating point normalization
   H5Tget_offset	- get bit offset within type
   H5Tget_order		- get byte order
   H5Tget_pad		- get padding type
   H5Tget_precision	- get precision in bits
   H5Tget_sign		- get integer sign type
   H5Tget_size		- get size in bytes
   H5Tget_strpad	- get string padding
   H5Tinsert		- insert struct member
   H5Tlock		- lock type to prevent changes
   H5Tpack		- pack struct members
   H5Tregister_hard	- register specific type conversion function
   H5Tregister_soft	- register general type conversion function
   H5Tset_cset		- set character set
   H5Tset_ebias		- set exponent bias
   H5Tset_fields	- set floating point fields
   H5Tset_inpad		- set inter-field padding
   H5Tset_norm		- set floating point normalization
   H5Tset_offset	- set bit offset within type
   H5Tset_order		- set byte order
   H5Tset_pad		- set padding type
   H5Tset_precision	- set precision in bits
   H5Tset_sign		- set integer sign type
   H5Tset_size		- set size in bytes
   H5Tset_strpad	- set string padding
   H5Tunregister	- remove a type conversion function

Compression
   H5Tregister		- register a new compression method

This release has been tested on UNIX platforms only; specifically:
Linux, FreedBSD, IRIX, Solaris & Dec UNIX.


Release information for parallel HDF5
-------------------------------------

+) Current release supports independent access to fixed dimension datasets
   only.

+) The comm and info arguments of H5Cset_mpi are not used.  All parallel
   I/O are done via MPI_COMM_WORLD.  Access_mode for H5Cset_mpi can be
   H5ACC_INDEPENDENT only.

+) This release of parallel HDF5 has been tested on IBM SP2 and SGI
   Origin 2000 systems.  It uses the ROMIO version of MPIO interface
   for parallel I/O supports.

+) Useful URL's.
   Parallel HDF webpage: "http://hdf.ncsa.uiuc.edu/Parallel_HDF/"
   ROMIO webpage: "http://www.mcs.anl.gov/home/thakur/romio/"

+) Some to-do items for future releases
      support for Intel Teraflop platform.
      support for unlimited dimension datasets.
      support for file access via a communicator besides MPI_COMM_WORLD.
      support for collective access to datasets.
      support for independent create/open of datasets.