[Info-vax] Empty blocks in FILES-11 directory files.

[Mark Daniel]

It seems as if directory blocks containing zero file entry records, and 
subrecords, tend to accumulate in active directories.  Can only assume 
these arise when multi-multi-multiversion consecutive file names are 
deleted from the directory.  Recently encountered 32 consecutive empty 
blocks at which my code sanity checked.

Quick solution; create an equivalent directory and copy from the 
original to the new.  Problem Solvered.  Assume a backup-restore would 
accomplish similar, etc.

Questions:

Is this expected directory file behaviour?

Do these empty blocks continue to accumulate, only to be reused should 
in-order file names be created?

Do extensive empty directory blocks represent tangible overhead to the 
(persumably) XQP?  (My code sanity checked at 32 but who knows exactly 
how many there really were.)

Are their tools to measure such directory file efficiency (shall we say) 
and to "compress" such files (apart from backup-restore).

TIA, Mark.

PS. I do recall descriptions of the FILES-11 directory internals being 
very simple-minded and inefficient.

PPS. My entire technical hard-copy collection, including such VMS tomes 
as McCoy's File System Internals, in a fit of pique, went into a recycle 
bin some years ago.  Moral of the story; don't let line-management get 
under your skin.

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