International Business Machines Corporation

Wade H Allen

Raymond A Thornton

Theodore M Cory

Patrick J Hurley

A system in which a device or machine is controlled by instructions from a data processor is provided which minimizes main memory storage requirements. An interrupt service routine monitors the input to the processor received from the device in response to control instructions sent by the processor. The interrupt service routine monitors this response for exception conditions. When an exception condition indicating that the device is no longer capable of fully carrying out processor instructions is received by the interrupt service routine, it activates an exception handler routine. A primary memory storage stack normally supports the interrupt service routine. However, upon the activation of the exception handler routine, this primary storage stack is switched to support the exception handler routine, and a secondary stack of significantly lower storage capacity is placed in support of the interrupt service routine which should have lower purported storage requirements during the active period of the exception handler routine. This results in a substantial saving of main processor memory capacity which otherwise would have to be dedicated to the support of the two respective routines.

Switching of programming routine supporting storage stacks

An electronic office equipment network has a plurality of work stations (11) and a plurality of printers (--, 14, 15, 16) connected to a network bus (12). The printers have various options installed as for example hardware attachments for feed paper (22). The network also has a printer resource manager (17) for receiving requests for a printer from the work stations and notifying a work station when a printer can be claimed by the work station. The process of claiming a printer includes the step of specifying those printer options which are required by the work station in order to properly format the printer data stream and control the printer. One such option is the paper feed technique to be used by the printer. The user is given the option of choosing the currently installed printer options thereby allowing the printer to specify the options to the work station.

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Austin, TX, United States of America

Wade H Allen