Master object table (MOT)

When an object was created, it was assigned a free entry in the MOT. This entry contained the unique name of the object and the primary absolute pointer to the representation of the object. When an object was destroyed, the unique name in the MOT entry for the object was replaced by the unique name to be used by a new object with the same MOT index. The value part of a capability for an object contained the index of the MOT entry for the object, and the unique name of the object. Whenever the absolute address of the representation of an object was to be obtained from a capability, the unique name in the capability was checked against the unique name in the MOT entry. Thus, there was no need to find and invalidate all capabilities for an object that was destroyed, as subsequent unique name checks would fail.