Galileo Spacecraft Pages
Appendix E. EPD File Structure
Table of Contents:
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:
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:
Next: 2. Record Header
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Updated 10/19/04, T. Hunt-Ward