Tape Line Disciplines

[neil at gid.co.uk]

If I have a VMS tape I can happily read it on my Unix box, because Unix
regards a tape as just an unstructured byte stream, ok I need a program
to do the conversion but that is a detail.

Now what if I what to require that all my tapes have a specific format,
say at least a header that includes a serial number, or equally that
they should be written in a VMS format. I can do this in a discretionary
way quite easily, could either modify the programs in question or pipe
out through a filter. Now say I have third party software, without
source - no program hack possible.

Could the following be done (or has it been done):-

How about the concept of a `tape line discipline' that means that when a
tape is opened and number of validations could take place (e.g. serial
number, am I allowed to use this tape, 101 different things). The device
close routine might update the header for me.

The concept of allocating drives and "mounting" tapes becomes a possibility.

Thoughts ?

Neil