Diagnostic Level  Duration  Description
----------------  --------  ---------------------------------------------------
 Level 5           3 sec    Extremely quick and superficial general maintenance
                            scan performed by the computer.
                             Note: The system being tested can operate under
                            Yellow and Red Alert.
 Level 4           5 min    A little slower, more of a complete scan. Normally
                            used during a shift change in order to generate an
                            accurate report for the duty officer.
                             Note: The system in question is to remain
                            on-line during this test.
 Level 3           30 min   Very complete scan. This scan is used on computer
                            systems only.
                             Note: The system in question can remain
                            on-line during this test.
 Level 2           1 hour   This is a combination of computer scans which must
                            then be verified by an engineer. Not an exhaustive
                            scan and subject to errors.
                             Note: The system in question should be
                            shut down before this test can be performed.
 Level 1           4 hours  The most thorough check possible. Involves
                            systematically taking each component apart and
                            testing it, as well as all power couplings.
                             Note: The system in question must be
                            off-line during this test.