4.1 SAX Final Observation Tape Layout

The FOT is a sequence of tape files, each one separated by a tape mark, and terminated by a double tape mark.

Physically each file is in "fixed blocked" format, i.e. all tape blocks are of the same length (in a file; this length may differ from one file to another) with the exception of the last block which may be shorter. All block lengths are multiple of a common logical record length.
The filing process is essentially the unblocking and the reconstruction of disk files with the original record lengths.

Top level FOT layout

• one tape directory file
• a group of files relevant to the entire observing period
• an instrument dataset for one SAX instrument
• another instrument dataset
• and another ... etc. etc.

  The instrument order is typically by increasing energy (LECS MECS HPGSPC PDS) or number (WFC1 WC2). NFI and WFC data are never mixed on the same FOT.

• Observing period related file group

  • one ephemeris file
  • one reconstructed attitude file
  • one OBT to UTC conversion file
  • zero or more spacecraft HouseKeeping (telemetry) files

  Instrument dataset

  • one instrument dataset directory (instdir)
  • zero or more observation filesets for the ingoing slew
  • one or more observation filesets for the target pointing
  • zero or more observation filesets for the outgoing slew

    Observation fileset

    • one observation directory (obsdir)
    • one experiment configuration file (expconf)
    • one (or none) instrument HouseKeeping (telemetry) file
    • one or more instrument Engineering (telemetry) file
    • zero, one or more instrument science (telemetry) file

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