VMS Help CMS, SHOW, HISTORY, Qualifiers, /UNUSUAL  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Controls whether transactions recorded as unusual occurrences
    are displayed. If you specify /UNUSUAL, only unusual transactions
    are displayed. By default, /NOUNUSUAL displays all transactions,
    including unusual occurrences. The following CMS transactions are
    defined as unusual occurrences:

    o  A RESERVE command specifying an element that is already
       reserved
    o  A concurrent replacement
    o  A VERIFY/RECOVER command
    o  A VERIFY/REPAIR command
    o  A CONVERT LIBRARY command
    o  A REMARK/UNUSUAL command