Dan Packman raises an important issue in that a single precision
variable doesn't give enough accuracy for time in some circumstances.
A more elegant solution than having two time variables would be to have
double precision dimension variables. I think that IEEE double precision
has enough bits to keep millisecond time for 10000 years -- it takes
49 bits to do this. If dimension variables can be only single or
double precision, I would choose double precision. This would not
waste much space in situations where such precision wasn't needed, so
the overhead would be small.
Dave Raymond
raymond@kestrel.nmt.edu