Subject: New version of FITS Product Conformance Tester

From: bschlesinger at nssdca.gsfc.nasa.gov (BARRY M. SCHLESINGER)
Date: 25 May 1993 16:53 EDT

A revised prototype of the developing NOST FITS Support Office
software package to validate FITS files is now available for testing.
It is written in ANSI C.  As before, the FPCT checks for the presence
of the required keywords in the primary header and whether or not they
are in the proper order. It will find them if they are out of order
but will issue warnings. Syntax is also checked.  Also, if the user
chooses, it creates a file of selected members of integer data arrays,
as specified by the user, unless there are major header errors.  This
version cannot handle floating point. If there are minor header 
errors, it will attempt to derive information to obtain the data array
but will warn the user that the data may not be extracted properly.
The current version does not check extensions. 
	
A number of changes have been made since the previous version, among 
them the following:

The software now checks whether named input files are successfully 
allocated, printing an error message and stopping execution when 
errors are detected.

Special data types are defined for the data being read from the FITS 
file; a sequence of typedef statements can be revised by the user as 
appropriate to the hardware.

The summary diagnostic has been split in two four separate messages: 
one for the header evaluation, one for the input file, one for allocation 
problems, and one for the data evaluation.  The condition codes now 
make 0 a normal return, with progressively higher digits for each 
evaluation signifying progressively more serious problems.  

Comments, particularly on errors and portability problems, are
solicited.  We are concentrating at present on making the program
itself function, and saving revisions of the interface, however
awkward it may be at present, for later. The software has been
developed on a VAX cluster.  It can operate on machines that use twos
complement integers with either most significant byte or least
significant byte first, but not on ones complement hardware.
ASCII-EBCDIC conversion also has not been implemented.  Sun users
should be warned that because the software is ANSI C, they will not be
able to use SUN C1.0, the standard compiler for SPARCstations. 

To obtain a copy of the package and the instructions for use, 
send electronic mail to

	(Internet) fits at nssdca.gsfc.nasa.gov
	(NSI-DECnet) NCF::FITS	

				Barry Schlesinger
				NOST FITS Support Office