System items and the MQAI

• The generation of PCF headers. System items can control the PCF command identifier, control options, message sequence number, and command type.
• Data conversion. System items handle the character-set identifier for the character-string items in the bag.

Like all data items, system items consist of a selector and a value. For information about these selectors and what they are for, see MQAI Selectors.

System items are unique. One or more system items can be identified by a system selector. There is only one occurrence of each system selector.

Most system items can be modified (see Change information within a bag ), but the bag-creation options cannot be changed by the user. We cannot delete system items. (See Delete data items.)