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

[Oswald Knoppers]

Op zaterdag 24 september 2022 om 19:31:31 UTC+2 schreef 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. 
> 
> -- 
> Anyone, who using social-media, forms an opinion regarding anything 
> other than the relative cuteness of this or that puppy-dog, needs 
> seriously to examine their critical thinking.

You can install dfu (https://www.digiater.nl/dfu.html). This utility has an option to compress directory files.

Oswald