The Catalina scheduler was developed to serve as a maintainable,
extendable external scheduler for LoadLeveler and other resource
managers.  Support of the GridForm Advance Reservation API was
one of the goals of the development effort.  Python was chosen
as the development language, to encourage readability.

  Catalina is similar to the Maui Scheduler in many ways:
    - Single queue, priority-based
        Both Maui and Catalina consider all the jobs on a machine in
        a single queue, and schedule them based on a priority calculation.
    - Reservations
        Both schedulers support restriction of jobs from nodes for set
        time intervals, based on job characteristics.
    - Backfill
        Both schedulers effectively run low-priority jobs, as long as
        they don't delay higher priority jobs.
    - Standing Reservations
        Both schedulers allow specification of recurring reservations.

  Catalina is missing several important Maui (version 3.0.3.7) features,
including: 
    - fairshare
    - job statistics tracking
    - workload profiling.

  Catalina is consistent with the GridForum Advance Reservation API,
although it does not support all features of the API.  Supported
features include:
    - creating a reservation
    - modifying a reservation
    - binding a reservation to a job
    - canceling a reservation.

  Unsupported features are:
    - two-phase commit
    - claiming a reservation
    - registering a callback function

  Catalina has several other distinguishing features:
    - shortpools.  These are virtual sets of nodes guaranteed to be available
      after a configurable lag time.  For example, Catalina can guarantee
      that 32 nodes will be available for the first high priority job to
      enter the queue, after a maximum of 8 hours queue wait time.
    - arbitrary Python code for filtering of jobs allowed to use a reservation.
    - arbitrary Python code for filtering nodes considered for use in a
      reservation.
    - user-settable reservations.  This feature allows an unprivileged user
      to create a reservation for himself or herself, subject to site policies.
      This would also allow application level metaschedulers to create
      reservations without requiring administrative privileges on the local
      cluster.

  Performance and functionality has proven adequate in production on
the SDSC Blue Horizon IBM SP.