HISTORY
. History records are stored in a structure array
component called RECORDS
, which is extended in multiples of
EXTEND_SIZE
, the current record (ie. the last used)
being denoted by CURRENT_RECORD
. A trace of such a
structure looks like,
New history records use up the unused slots first, the array being extended on demand. The purpose of theHISTORY{structure} CREATED <_CHAR*18> "dd-mmm-yy hh:mm:ss" EXTEND_SIZE <_INTEGER> 10 CURRENT_RECORD <_INTEGER> 17 UPDATE_MODE <_CHAR*8> "DISABLED"|"QUIET"|"NORMAL"|"VERBOSE" RECORDS[20] {array of structures} Contents of RECORDS[1] DATE <_CHAR*30> "dd-mmm-yy hh:mm:ss" COMMAND <_CHAR*30> "XSORT Version 1.6-1 " TEXT[n] <_CHAR*80> ...
UPDATE_MODE
component is to allow history
updating to take place at different levels on a file by file basis. The
four options are self-descriptive and are, disabled,
quiet, normal and verbose.
ASTERIX implements all of these levels, but does not distinguish between
normal and verbose. In quiet mode ASTERIX
writes only the date, command and host name to the history record. In
normal and verbose modes the text records are also written.
HISTORY
keywords thus,
In addition the keywords DATE and CREATOR are written if the FITS file is being created ab initio, and the HSI_NEW routine is used. Where ASTERIX programs add history to FITS files not created originally by ASTERIX, all the existing HISTORY records are considered to comprise a first history record, with time stamp and command taken from the DATE and CREATOR keywords if defined.HISTORY ASTERIX: Created by COMMAND at DATE on HOST HISTORY text line 1 ... HISTORY text line n
David J. Allan (dja@star.sr.bham.ac.uk)