The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 26, 2002
Filed:
Mar. 19, 1999
David Reid Eaves, Mission Viejo, CA (US);
Unisys Corporation, Blue Bell, PA (US);
Abstract
An I/O device is shared between a host operating system, and a foreign operating system that runs under the host operating system, in a single computer. The I/O device must be of a type which includes a port driver that receives device commands for reading addressable fields on a removable data storage media. Each media which is to be a source of data for the host operating system stores a first identifier in a particular addressable field, and each media which is to be a source of data for the foreign operating system stores a second identifier in a particular addressable field. A registry in the host operating system indicates that the I/O device is to be used exclusively by the host operating system; so the host will try to use the I/O device. But in addition, a different private registry in the foreign operating system indicates how that operating system can address the I/O device; so the foreign operating systems will also try to use the I/O device. Each time the host operating system attempts to use the I/O device, it looks for the first identifier on the storage media; and it terminates its attempt if the first identifier is not found. Each time the foreign operating system attempts to use the I/O device, it looks for the second identifier on the storage media; and it terminates its attempt if the second identifier is not found.