The Universal File Format 58 has been the defacto standard for the experimental dynamics community, specially in the area of modal analysis. The format defines a header that contains general information about the data contained in the file (function type, response direction, etc) as well as channel specific information (channel name, units, data type, etc). To reduce storage space as well as loading time, the binary universal file format was introduced. This files contain the same information as the ASCII type, the only difference is the way the data values are stored.
The Universal File Format header is divided in records 80 characters long that contain one or more fields of information. The first record is a delimiter and has to have -1 in the first six columns. The file also needs to have a stop record at the end of the data values with the same form as the first record. The second record specifies the storage type of the data values: 58 for ASCII and 58b for binary. This particular record has more fields on the 58b specification since it contains binary data specific information such as byte order.
The format support the definition of the Abscissa channel in terms of abscissa minimum and abscissa increment values or by specifying each abscissa value. If the data is evenly spaced, you can save disk space by storing your abscissa channel implicitly. The format also supports the storage of complex data for the Ordinate channel as well as the definition of a Z channel and a Ordinate denominator channel. This features are not supported by the Universal File Format driver.