I follow the discussion about tuning standards with interest.  I have
a A=440 tuning fork, which I picked up at a flea market.  I also use
the 'Instrument Tuner' in Apple's 'Garage Band'.  It seems to me that
the reference frequency in 'Garage Band' should be program-adjustable
from A=440 to whatever, so that the computer could be tuned to an
instrument rather than vice-versa.

Regards from Paul Rumpf,
Melbourne, Australia