Copyright © 2006 Laboratorio de Sistemas, GSyC, URJC. All Rights Reserved Copyright © 2002 Lucent Technologies Inc. All Rights Reserved This is Plan B 4rd edition. Most of it is Plan 9 from Bell Labs 4th edition taken verbatim. The system has been changed and includes technology from Plan B 2nd and 3rd edition. See the various LICENSE files for licensing conditions. The Laboratorio de Sistemas does not add any further requirements.