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2 Introduction

 

The information and exercises described in Chapter 4 are intended for asking the basic question ``Did OSSE see the object?''. As part of this process, data files are created which provide a good ``stepping-off'' point for more detailed analyses. Some of these more detailed analyses are described in Chapter 5. These exercises make use of a number of high-level routines in IGORE.

The OSSE spectral analysis applications support SDB header version 7 only. Information on the most common SDB AUX records are given in Chapter D.

It is important to note that, for many of the spectral analysis applications, the indirect SDR fields (e.g., the HDR, DAT and ERR fields, etc.) need not be resident in memory to successfully execute the application, as long as valid FILE and TAG fields are available in the SDR. If the required indirect field is not available in memory (e.g., it has not been read into the SDR with either SDB$READ or SDR$GET),    the application will attempt to read the required information directly from the SDB file using the FILE and TAG fields contained in the SDR. The search for the SDB file using the FILE field is performed in the following sequence:

Note that the applications SDB$OPEN  and SDR$GET search for the SDB file in the same order. The application FILE_INFO  may be used to determine which files are open and the associated logical unit.

IGORE creates, maintains, and uses records in a nested hierarchical system, allowing record structures that are more complex than the structures allowed by IDL. These IGORE records are not directly accessible to IDL. Instead, IDL variables are created as pointers to these IGORE records. It is therefore important to note the distinction between IGORE records and structures versus IDL records and structures.

A subset of the IGORE routines can be used to move data between IGORE and IDL variables. The routines include; GETFLD, PUTFLD, GETAUX, PUTAUX, GETAUXREC and PUTAUXREC.

Many of the routines that create and manipulate IGORE records accept optional keywords, including NAME  and /UNIQUE . These keywords allow the user to explicitly specify the name of an IGORE record, or to force a unique name to be generated, respectively. By default IGORE record names are assumed to match the names of the IDL variables used as record pointers.

See the IGORE User's Guide for a full discussion of the IGORE philosophy and the related usage considerations.


Next: 3 How to Retrieve Up: OSSE Guest Investigator Guide Previous: 1.6 Acronyms and Glossary