The Truncate Feature.

This feature is a scheme whereby filing systems which cannot handle long
filenames for one reason or another can be controlled as to what they do
about it. Under normal circumstances they used to give a 'Bad name' error if
a long filename was passed to them. Under the new scheme this property can
be changed so that when they are given a long filename they truncate it
before using it.

This is controlled by the *configure Truncate command. Two possible
parameters are allowed: Configure Truncate on and Configure Truncate off.
This controls the CMOS byte &1c, bit 0. Bit 0 being 0 means off and 1 means
on. When the Truncate bit is on then filenames will be truncated instead of
errors being generated.

As a filing system this bit should be read (and other bits in that byte
masked off) when the filing system is initialised.
