Force RAO off or linear for different tape label formats

Problem to solve

Fermilab's Enstore and EnstoreLarge tapes have dummy block numbers which give wrong results with RAO.

Stakeholders

Former Enstore users (Fermilab, PIC, perhaps others).

Proposal

The idea floated at the meeting today was to allow the Enstore read sessions to either turn off RAO entirely for their session or set an algorithm (I think this is Linear) that will access files on the tape in fSeq order. This is the most efficient way to access files if the block numbers of the files are not known.