A remote command traversing the Global network may be held up at a particular location (for example, due to a communications fault). For most commands, the stalled command is placed in a transaction database at that location. The transaction database records the state of the command so that it can be processed later. This means that commands are guaranteed to succeed at some time in the future, but that this time cannot be predicted. Refer to Monitoring Command Progress for further information about the transaction database, and how to monitor the progress of commands.

A small number of commands, known as ‘kernel’ commands, bypass the transaction database and are stored in a pending file for later processing. An example is the ISOLATION command which isolates a location.

Other kernel commands are LOCK and UNLOCK and, in relation to a Satellite’s transaction database, the ALLOCATE and CHANGE PRIMARY commands. Refer to Pending File for further information.