Universität UlmFakultät für InformatikAbteilung RechnerstrukturenDesign of theSPEEDOSOperating System KernelDissertation zurErlangung des Doktorgrades Dr. rer. nat.der Fakultät für Informatikder Universität Ulmvorgelegt vonKlaus Espenlaubaus Biberach a.d. Riß2005Official Copy, serial number df13c6b7 d6ed e3f4 58b6 8662375a2688Amtierender Dekan: Prof. Dr. Helmuth PartschGutachter: Prof. Dr. J. Leslie Keedy (Universität Ulm) Prof. Dr. Jörg Kaiser (Otto von Guericke Universität, Magdeburg)Gutachter: Prof. John Rosenberg (Deakin University, Geelong, Victoria, Australia)Prüfungstermin: 11.07.2005iiiAbstract(Eine inhaltsgleiche, deutsche Fassung dieser Übersicht ist ab Seite 243 zu finden.)The design of current operating systems and their kernels shows deficiencies in re specttothestructuringapproachandtheflexibilityoftheirprotectionsystems. Theoperatingsystemsandapplicationssufferunderthislackofextensibilityandflexib ility. Theprotectionmodelimplementedinmanyoperatingsystemsisnotpowerfulenough to represent arbitrary protection conditions on a more fine grained granu laritythangivingreadand/orwriteaccesstoanentireobject. Additionallycurrentoperating systems are not capable of controlling the flow of information betweensoftware units effectively. Confinement conditions cannot be expressed explicitlyand thus confinement problems can only be solved indirectly.