I don't know if this behaviour is a bug but I thought it worth
reporting because it seems odd to me.

I have a field in a database defined as

ORIGHARDDISKSIZE NUMERIC(4,1),

If I feed sensible numbers into this field all is well.

If I feed numbers that are too big into this IBO generates an
EIB_ColumnError with the message "Smallint Overflow".

Essentially the point is that the error is nothing to do with
smallints The field isn't a smallint its a numeric.

{I suppose its possible that Interbase is doing some internal
conversion that I'm not aware of}

I'll solve the problem by redefining the database field for now.