Abstract: A method for allowing a system programmer using a computing system to efficiently use a queuing lock without the requirement of pre-allocating qnode structures for each possible thread of computation expecting to use the lock. More specifically, the lock structure of this invention uses two pointers: a head pointer that points to the next qnode structure representing the next thread or process interested in acquiring the lock, and a tail pointer pointing to the qnode structure representing the last thread or process in a queue of threads or processes awaiting to acquire the lock. When the lock is released, a flag is changed in the qnode structure of the next thread in line (pointed to by the head of the lock) indicating that thread now has the lock and may proceed. A thread or process obtains the lock by spinning on a flag in a qnode structure representing such thread or process.

Abstract: A method and apparatus for performing efficient interprocess communication (IPC) in a computer system. With this invention, a memory region called the IPC transfer region is shared among all processes of the system to enable more efficient IPC. The unique physical address of the region is mapped into a virtual address from each of the address spaces of the processes of the system. When one of the processes needs to transfer data to another of the processes, the first process stores arguments describing the data in the region using the virtual address in its address space that maps into the unique physical address. When the other or second process needs to receive the data, the second process reads the data from the second region using the virtual address in its memory space that maps into the unique physical address. With this invention, in most cases, control of the IPC transfer region occurs automatically without any kernel intervention.

Abstract: In a computer system, a method and apparatus for scheduling activities' access to a resource with minimal involvement of the kernel of the operating system. More specifically, a “next bid” is maintained, and this parameter identifies the highest bid for the resource by any activity not currently accessing the resource. The accessing activity then compares its bid, which can be time varying, with the “next bid” to determine whether it should release the resource to another activity. The “next bid” can be accessed without any system calls to the operating system. This allows the activity to determine whether to relinquish control to the system without the necessity of communication between the two. Likewise, the operating system can access the bid of the accessing activity without explicit communication. This allows the system to determine whether to preempt the accessing activity without the necessity of communication between the two.

Abstract: A method and apparatus for performing efficient interprocess communication (IPC) in a computer system. With this invention, a memory region called the IPC transfer region is shared among all processes of the system to enable more efficient IPC. The unique physical address of the region is mapped into a virtual address from each of the address spaces of the processes of the system. When one of the processes needs to transfer data to another of the processes, the first process stores arguments describing the data in the region using the virtual address in its address space that maps into the unique physical address. When the other or second process needs to receive the data, the second process reads the data from the second region using the virtual address in its memory space that maps into the unique physical address. With this invention, in most cases, control of the IPC transfer region occurs automatically without any kernel intervention.

Abstract: A zoom control mechanism includes a context display for displaying a representation of a data set, a zoom display for displaying a representation of a zoom interval within the data set, a context indicator that indicates a start point or an end point of a zoom interval within a context display, and a zoom indicator, corresponding to the context indicator, that indicates the start point or end point of the zoom interval within the zoom display. The zoom interval is updated according to user selection and movement of the context indicator and the zoom indicator to a new location within the context display and the zoom display, respectively.

Abstract: A zoom control mechanism includes a context display for displaying a representation of a data set, a zoom display for displaying a representation of a zoom interval within the data set, a context indicator that indicates a start point or an end point of a zoom interval within a context display, and a zoom indicator, corresponding to the context indicator, that indicates the start point or end point of the zoom interval within the zoom display. The zoom interval is updated according to user selection and movement of the context indicator or the zoom indicator to a new location within the context display and the zoom display, respectively.