Kerrighed
		     ---------

These are the release notes for Kerrighed 


WHAT IS KERRIGHED ?

	
  Kerrighed is a Single System Image operating system for clusters.
  Kerrighed offers the view of a unique SMP machine on top of a
  cluster of standard PCs.

  Kerrighed is implemented as an extension to Linux operating system
  (a set of Linux modules and a small patch to the kernel).

  Kerrighed main features are :

    * Customizable Cluster Wide Process Scheduler.

        Processes and threads are automatically scheduled over the
        cluster nodes to balance the CPU load using the Kerrighed
        default scheduling algorithm. However, Kerrighed offers a
        toolkit to easily write customized schedulers hot-loadable
        through kernel modules.

    * Cluster Wide Shared Memory.

        Threads and System V memory segments can operate through the
        whole cluster, just like on an SMP machine.

    * High Performance Stream Migration Mechanism.

        Processes using streams (socket, pipe, fifo, char device, etc)
        can be migrated with no penalty on communication performance
        after migration.

    * Distributed File System.

        A unique file name space is seen over the whole cluster. All
        cluster disks are merged in an unique virtual disk in a
        customizable RAID-like fashion.

    * Process Checkpointing.

        Processes can be checkpointed and restarted on any cluster
        node.

    * Full Posix Thread Interface.

        The full Posix Thread interface can operate with threads
        spread over cluster nodes.

    * Cluster Wide Unix Process Interface.

        All traditional UNIX process management commands (top, ps, kill,
        etc) operate cluster wide. Moreover, process identifiers (pid)
        are unique cluster wide.

    * Customizable Single System Image Features.

        Single system image features (shared memory, global scheduler,
        migrable streams, etc) can be enabled or desabled on a per
        process basis.

  The present implemention of Kerrighed is compatible with version
  2.6.20 of Linux kernel.
  Kerrighed functionalities have been added to the Linux kernel through 
  modules and some minor kernel modifications.