Unisys Corporation

John A Keller

Andrew T Jennings

Philip A Murphy

Robert H Tickner

Timothy D Updegrove

Barry S Traylor

A system and method are disclosed for providing computers, particularly the Unisys A series computers, with the capability to function with disk drives of more than one sector format, especially if a predetermined sector format is inefficient and/or cost prohibitive. Interfacing is provided for processing I/O requests between a predetermined logical sector format (e.g., 180 byte sectors) and a variable physical sector format (e.g., 512 or 720 byte sectors). Read operations compare read request addresses to physical sector boundaries and discard unwanted data. Write operations, using at least one sector buffer, perform a read/modify/write cycle, such that the necessary physical sector data not associated with the write request is read into the sector buffer, modified and written back to the disk along with the write data inserted at the appropriate location. This system and method can effectively increase the usable capacity of selected disk drives by 15-20%.

System and method for providing variable sector-format operation to a

A mechanism for queuing a set of happened events in order of their occurrence and allowing for multiple occurrences to result in multiple processing iterations which mechanism maintains a multi-event table which is really a table of multi-event designations to be allocated to different processes upon request where the requesting processes assign a particular function with each multi-event entry and each of its own related event designations. The mechanism of the present invention maintains the state of such allocated multi-event entries in the multi-event table and signals the related or ('receiving') process that an event has happened within that set, and, if there are multiple events in the set which are happened, which of those events, occurred first by returning the events signature so that the particular system central processors assigned to execute those particular processes may then proceed with their execution and perform whatever processing is required for that particular event needing attention first.

Multi-event mechanism for queuing happened events for a large data

A task control mechanism for maintaining a queue of ready or available processes linked together according to an assigned priority for a plurality of central processors where the processors may be assigned to the highest priority task when that processor is not busy executing some higher priority task. The task control mechanism also includes a mechanism for computing task priorities as new tasks are inserted into the queue or removed. The mechanism also maintains an event table which is really a table of event designations to be allocated to different processes upon request where the requesting processes assign a particular function or 'meaning' to the event designation. The mechanism of the present invention maintains the state of such allocated events in the event table and signals the related (or 'waiting') processes that an event has happened so that the particular system central processors assigned to execute those particular processes may then proceed with their execution.

Special purpose processor for off-loading many operating system

An event allocation mechanism in a processing system which mechanism maintains an event table which is really a table of event designations to be allocated to different processes upon request where the requesting processes assign a particular function or 'meaning' to the event designation. The mechanism of the present invention maintains the state of such allocated events in the event table and signals the related (or 'waiting') processes that an event has happened so that the particular system central processors assigned to execute those particular processes may then proceed with their execution.

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Coatesville, PA, United States of America

John A Keller