Re: 3-word compound adjectives; the return of the '-'

[Tadziu Hoffmann]

>  a) block device-based filesystems
>  b) block-device-based filesystems
>  c) block- device-based filesystems
>  d) block device\[en]based filesystems
>
> Which form would you recommend me to use?

I would go with "block-device\[en]based filesystems", with
the reasoning that a dash binds stronger than a space, the
precedence being (from stronger to weaker binding):

  [none] > hyphen > en-dash > space

Similarly:

  hot-fudge sundae

and

  Einstein\[en]de-Sitter universe

even though other people may disagree on this point.
(de Sitter as a name is without hyphen, but I would
hyphenate it in a compound to make the relationship
between the words clearer.)

On the web and in the literature you can find

  Anti-de Sitter space

which I would prefer to see as

  Anti\[en]de-Sitter space

Although language does not always follow logic, in reference
manuals and the like exactness should be preferred over
traditional custom.  This also pertains to moving punctuation
outside of quotes, if it is not part of the quoted text, e.g.,

  This is referred to as a "file system".

instead of

  This is referred to as a "file system."