Lucent Technologies Inc.

Christopher Allen Small

Abraham Silberschatz

Eran Gabber

John Louis Bruno

Jose' Carlos Brustoloni

A computer operating system in which transfer of control of executing threads between protection domains is implemented using specific portals dedicated to the particular transfer of control between two protection domains. The transfer of control may also include parameter manipulation. A server registers a portal specification with a portal manager, the portal specification defining the behavior of portals which transfer control to the server. Thereafter, when a client application desires service from the server, the client application requests instantiation of a portal which will transfer control of an execution thread from the client application protection domain to the server protection domain. Upon receipt of the request, the portal manager dynamically generates portal code and updates a portal table associated with the client application, thus instantiating the portal. When the client application desires to invoke the server, the client application issues a system call instruction which results in switching the processor to privileged mode, followed by a lookup to the portal table and a transfer of control to the portal code identified in the portal table. The execution of the portal code results in transfer of control of the execution thread to the protection domain of the server. Various parameter manipulation techniques are disclosed for improving the efficiency of the transfer of control.

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New Providence, NJ, United States of America

Christopher Allen Small