The nonstandard stuff could not be found in in the first pubslished versions

of the program. The first version I am aware of, is a program called 0126136

SUGtar published at the Sun User Group meeting in december 1987, a different

publishing of the same program which has been originally written by

John Gilmore was called PDtar. In 1987 PDtar/SUGtar was implementing a true

subset of the 1987 POSIX-1003 draft (missing only the long name splitting).

FSF people then later added t_atime... making GNU tar non POSIX compliant.

When FSF added the sparse file handling stuff, this was done in a way that

even violates any tar document available since the late 1970's.

GNU tar is not tar...