International Business Machines Corporation

George David Timms, Jr

Paul LuVerne Godtland

Michael Joseph Corrigan

Wade Byron Ouren

Richard Karl Kirkman

An operating system kernel includes an attach mechanism and a detach mechanism. In addition, processes are tagged with an access attribute identifying the process as either a client process or a server process. Based on the access attribute, the operating system kernel lays out the process local address space differently depending on whether the process is a client process or a server process. A server process can 'attach' to a client process and reference all of the client process' local storage as though it were its own. The server process continues to reference its own process local storage, but in addition, it can reference the other storage, using the client process' local addresses. When access to the other storage is no longer needed, the server process can 'detach' from the client process. Once detached, the other storage can no longer be referenced.

Method, apparatus, and computer program product for accessing process local storage of another process

An apparatus and method provide simultaneous local and global addressing capabilities. A global address space is defined that may be accessed by all processes. In addition, each process has a local address space that is local (and therefore available) only to that process. An address translation mechanism is implemented, preferably in hardware, to compare an address to defined addresses for local and global addressing and to detect when a virtual address computation result would go outside a boundary for the appropriate addressing scheme. The address translation mechanism maps a virtual address to a corresponding physical address, and uses different criteria depending on whether the address is local or global. The address translation mechanism allows an instruction to operate on both local and global addresses by determining at run-time which address space is referenced, and by performing the necessary translation and boundary checking for either global or local address space, whichever is accessed by the instruction. By providing both global and local addressing for the same instructions, the apparatus and method of the present invention provide great flexibility in addressing, allowing a computer program to benefit from the advantages of both addressing modes.

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Rochester, MN, United States of America

George David Timms, Jr