{
  "status": "shipping",
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-18",
  "slug": "hdf5-virtual-dataset",
  "term": "HDF5 virtual dataset",
  "aliases": [
    "HDF5 VDS"
  ],
  "definition": "An HDF5 virtual dataset maps selections from source datasets into a single logical array without storing those source values in the virtual mapping itself.",
  "note": "Mapping: sources are identified by filenames, dataset paths and selections, and may be defined before the sources exist. Ordinary array reads follow the mapping. [h5py-vds]\n\nMissing input: unavailable mapped data can be returned as a fill value. A successful read therefore does not establish that every source was present. [h5-vds]\n\nResolution: HDF5_VDS_PREFIX can change where relative source names are found. A hash of the virtual file identifies its bytes, not every source selected by the reader environment. [h5-properties]\n\nMeasured example: Hesela's fixed-shape experiment returned zeros for a missing source and replacement integers after a prefix override, while the virtual file hash stayed unchanged. This is bounded API evidence, not a claim about every source failure. [hesela-vds]",
  "related": [
    "hdf5",
    "hdf5-fill-value",
    "backup-verification",
    "hdf5-hyperslab"
  ],
  "citations": [
    {
      "id": "h5py-vds",
      "title": "h5py 3.15.0: Virtual Datasets",
      "url": "https://docs.h5py.org/en/3.15.0/vds.html",
      "accessed": "2026-10-17"
    },
    {
      "id": "h5-vds",
      "title": "The HDF Group: Introduction to the Virtual Dataset",
      "url": "https://support.hdfgroup.org/documentation/hdf5/latest/_v_d_s_t_n.html",
      "accessed": "2026-10-17"
    },
    {
      "id": "h5-properties",
      "title": "The HDF Group: H5Pset_virtual source-file resolution and H5Pset_fill_value",
      "url": "https://support.hdfgroup.org/documentation/hdf5/latest/group___d_c_p_l.html",
      "accessed": "2026-10-17"
    },
    {
      "id": "hesela-vds",
      "title": "Hesela: HDF5 virtual dataset dependency observations",
      "url": "https://hesela.dev/datasets/hdf5-vds-dependencies/",
      "accessed": "2026-10-17"
    }
  ],
  "advantages": [],
  "limitations": []
}