Q:  How many IBM types does it take to change a light bulb?
A:  100. Ten to do it, and 90 to write document number GC7500439-0001,
    Multitasking Incandescent Source System Facility, of which 10% of
    the pages state only "This page intentionally left blank", and 20%
    of the definitions are of the form "A ...... consists of sequences
    of non-blank characters separated by blanks".