(under subclass 107) Subject matter comprising means or steps for saving and restoring state data (i.e., context) of a task, process, or thread in a preemptive, nonpreemptive, or cooperative multitasking system.
(1) Note. This subclass is directed to the specific implementation details of performing a context switch in a preemptive, nonpreemptive, or cooperative multitasking system.
(2) Note. Also included in this subclass is the user-implemented task or context switch between two or more application programs which are resident in memory at the same time. In this arrangement only the foreground application is given processing time. A user may manually activate a background task by bringing the window or screen of the background task to the front. An example of this type of task switch is when a user switches between a WINDOWS 3.1 (TM) program and a MS DOS (TM) program by invoking the Alt-Tab keypress combination.
(3) Note. A context switching is typically implemented with
interrupts and multitasking patents often use language directed to interrupts to explain how time-sharing takes place. Therefore, a patent directed to context switching and reciting interrupt processing is properly classified here. Interrupt processing, per se, is classified elsewhere. See the SEE OR SEARCH CLASS notes below.
SEE OR SEARCH CLASS
710, Electrical Computers and Digital Processing Systems: Input/Output,
260+, for interrupt processing, per se. 712, Electrical Computers and Digital Processing Systems: Processing Architecture and Instruction Processing (e.g. Processors),
228, for context preserving at the instruction computer level.
