2.1
Units: Basic stability calculations
are performed using weights, typically Ltons or Mtons. However, some
cargoes are more commonly measured in short tons, TEUs, or barrels.
Other liquid loads (fuel and ballast) might be initially measured
as soundings or ullages. The program developer may wish to make its
program more convenient for the user to enter data in these alternate
units. If so, the program should minimize chances for unit confusion
and, wherever possible, weight conversions should be calculated by
the computer. Screen displays and print-outs should then present both
the entered value and the computational weight value side-by-side.
2.2
Data and program protection: Although
the program should be flexible enough to allow the user to override
default data, certain data, such as lightship characteristics, allowable
bending stress, required GM, as well as the program itself, should
be protected against user revision. This could be achieved by furnishing
the ship with compiled or read-only versions.
2.3
Back-up of data: Copies of all
constant data residing in computer files, such as ship geometry and
tables, should be available on independent storage units, such as
tape of floppy disks. The number of such copies should not be less
than two.