The Midas Blue File is the standard binary file format used by modern Midas frameworks. Blue files are so ubiquitous in Midas applications that many people erroneously refer to a Blue file as simply a "Midas File". Blue files are designed to efficiently store one-dimensional or two-dimensional signal data as well as record-based information.
The Blue file format was preceded by the Gold file format. While X-Midas and NeXtMidas have the ability to import Gold files, they are no longer used. Many Gold files have been converted to Blue files, those that remain are usually found on tape archives. Users who are relatively new to the Midas community are unlikely to ever encounter a Gold file. (Important Note: These days when people refer to a "gold file" they are often using "gold" to mean a "gold-standard," or a file whose data has been proven valid. This terminology is frequently associated with test cases where the test output is compared to a reference output, called a "gold" file.)
Blue files start with a four-byte "magic number" equal to the ASCII code "BLUE" (see "Magic number (programming)" in Wikipedia for details). Because of this Blue files are often termed "BLUE" files, although the name is not an acronym. (This follows the use of "GOLD" for Gold files.)
The design of Blue files grew out of the Midas community over several decades. The definition of the Blue file format was officially codified in 2006. Please see Midas BLUE File Format / Version 1.0.0 (CCD-2006002-1.0.0).
Blue files are explained, in detail, in the official
Midas BLUE File Format / Version 1.0.0
(CCD-2006002-1.0.0) document, a copy of which is contained in the docs
area
of the NeXtMidas SYS
option tree. What follows below is a very brief overview of
Blue files.
Fixed | Basic information about the file (start values, deltas, units). |
Three keywords (called main header keywords). | |
Adjunct | Details about the file layout (varies based on file type). |
May include system modeling information. |