Fundamental Technologies

Galileo Spacecraft Pages

Appendix E. EPD File Structure

Table of Contents:

  1. Description of EPD File Header Record (below; please scroll down)
  2. Record Header
  3. Rate Block
  4. CMS PHA Block
  5. LEMMS PHA Block
  6. Rate Calc Block
  7. Binned Rate Averages

1. Description of EPD File Header Record

Source: T. P. Armstrong, March 1985

This record will be present at the beginning of all Galileo EPD sequential files which are written by the EPD processor or average processor. The purpose of this record is to carry along the descriptive information about the run. This information is obtained in several ways:

  1. From the system via calls to DATE.
  2. From the operator by echoing all operator responses to program prompts to a file.
  3. From the program and the input data set as a result of the run.

When EPD runs in a mode of writing its output file to disc, the file header record can easily be written into the first position on the data set. However, when END is writing a magnetic tape, it must first write a "dummy record" to hold the space at the beginning of the files for the file header record. When the run has completed successfully and the information needed for the file header record is available, END will rewind the tape and write the file header record in the first position. The record lengths must be carefully controlled in order to avoid overwriting into the second record or leaving an unerased fragment of the "dummy record" which would confuse and cause tape errors on subsequent attempts to read the output file.

The items which are included in the file header are:

  1. Program name
  2. Operator name
  3. Input file label
  4. Output file label
  5. Production date to begin run
  6. Production date to end run
  7. Input file start time
  8. Input file end time
  9. Input file number of time discontinuities
  10. Input file number of overlapping records
  11. Input file gap time--amount of missing time.
  12. Input file overlap time--amount of duplicate time.
  13. Input file number of successful reads.
  14. Input file number of unsuccessful (skipped) reads.
  15. Output file start time
  16. Output file end time
  17. Output file number of rate blocks
  18. Output file number of CMS PHA blocks
  19. Output file number of LEMMS PHA blocks
  20. Output file number of RATE CALC blocks
  21. Echo of program/operator interaction (ASCII)

Next: 2. Record Header

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Updated 10/19/04, T. Hunt-Ward
tizby@ftecs.com