The SAV file format is the default file format for the SPSS statistical program. PSPP also uses the SAV file format as its default file format. PSPP is an open source alternative to SPSS and is maintained by GNU foundation.
The header of the binary format starts with $FL2 (24 46 4C 32). After that the product code starts with @(#), after a space (or in hex: 20) the version of SPSS is show. Some exaples of versions are: SPSS DATA FILE MS Windows 17.0.0, IBM SPSS STATISTICS DATA FILE MS Windows 19.0.1 or GNU pspp 0.1.4 - sparc-sun-solaris2.5.2. The version numbers have different forms, but the version number has a fixed length field of 55 bytes (it is filled up with hex value 20 till the 55 bytes is met). The total length is 60 bytes. The next section contains different kinds of information about the file for example number of data elements per case or compression.
The section that start with Y@ (hex: 59 40) is the creation date and time. It is 17 bytes long. If the date and time is not available it is set to 01 Jan 7000:00:00. The date is in dd mmm yy format and the time is in hh:mm:ss format. After this information only a user-defined file label is added and the remaining part is filed with padding.