When I worked at IBM a couple of years ago (doing
rather dull tech
support stuff) I worked out that the password rules (something like
"eight to ten characters, two to four upper-case letters and two to four
digits not in the first, second, second-to-last or last position")
yielded about 1000 valid passwords...
IBM *never* had password rules like that.
It's "eight or more, at least one alphabetic, at least one
non-alphabetic". It used to be "eight or more, at least one
non-alphabetic, can't begin or end with a non-alphabetic".
Of course, GSD331 had its own weird requirements, but those are, by no
means, IBM's official rules for internal passwords.
For the systems that don't have short password fields, would'nt pass
phrases be more secure?