LAM has the hooks to allow a snapshot of process and message status to be taken at any time during an application run. On the second level, the MPI library is instrumented to produce a cummulative record of communication, which can be visualized either at runtime or post-mortem. Some of the in-daemon processes form a network communication subsystem, which transfers messages to and from other LAM daemons on other nodes. The network subsystem adds features like packetization and buffering to the base synchronization. Other in-daemon processes are servers for remote capabilities, such as program execution and file access.
Users can configure in or out services as necessary.
Application management and debugging are provided by a uniquely structured extensible daemon. The unique software engineering of LAM is transparent to users and system administrators, who only see a conventional daemon. This developer's mode is still transparent to users but exposes LAM's highly modular components to simplified individual debugging. It also reveals LAM's evolution from Trollius, which ran natively on scalable multicomputers and joined them to the UNIX network through a uniform programming interface. An important feature of LAM is hands-on control of the multicomputer.