I have begun to suspect that the locking is redundant. I think some implementations of ndbm do their own internal locking. On HPUX and possibly other systems, you should use ndbm instead of dbm. If your dbm is definately buggy, let me know so I can make a list of such systems. You may have to find an alternate way to handle timestamps or comment out that section of code.
Font addition is now trivial if each digit is a separate image.
If I add another font, it will be because the new digits are differently cool. I might change my mind later, and implement these anyway, but not this week.