At any one time, a resource is either in use or not in use, and is either enlisted or not enlisted in a transaction. This yields four possible resource states.
A resource which is not in use by a object and not enlisted in a transaction is in unenlisted inventory. A resource in general inventory is available for assignment.
A resource which is not in use by a object but is enlisted in a transaction is in enlisted inventory. Such a resource is available for assignment only to objects running in the same transaction. A resource moves from enlisted inventory to unenlisted inventory when MTS Executive notifies DispMan that the transaction is complete.
If a resource is assigned to a object, and the instance is not running in a transaction, or the resource dispenser has identified the resource as not transactional, then this resource is in unenlisted use.
If a resource is assigned to a object, and the instance is running in a transaction, and the resource dispenser has successfully enlisted the resource in the transaction, then this resource is in enlisted use.