When an index block scan is requested, IRRUT200 verifies that the following are all true:

• The pointer to every index block is a multiple of 4096.
• Every index block begins with the value X'8A'.
• Every index entry name has a valid length.
• Every pointer entry in the index block is preceded by the value X'6'x (x can be any value).
• Only level-one blocks appear in the sequence set.
• Offsets to the last index entry in each block are correct.
• Offsets to free space in each index block are correct.
• The offset table points to index entries.
• Every regular index entry must have a nonzero segment count.
• Every alias index entry must have a length consistent with the base profile data.