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. 29, 2000
Filed:
Aug. 01, 1997
Stephen C Robinson, Olathe, KS (US);
Darin J Beesley, Kansas City, MO (US);
Thomas H Walters, Gardner, KS (US);
Garmin Corporation, , TW;
Abstract
A system for buffering data has a processor connected to a memory for storing mass data, connected to a single buffer having a plurality of buffer storage locations in a chain, and connected to a plurality of counters, wherein each counter corresponds to one of the buffer storage locations. The processor selects a sector of memory containing desired data associated with an open file, scans the buffer storage locations to determine whether the data is in the buffer and, when the data is not within the buffer, reads the data from the selected sector of memory into a selected buffer storage location that is unallocated to an open file. The processor then points to that allocated buffer storage location, so that the data can be retrieved from the buffer for processing. As additional data is desired that is not found in the buffer, the buffer storage location allocated to the open file is de-allocated and, if not allocated to any other open files, moved to the beginning of the chain of buffers. The sector of data containing the desired data is then read into a selected buffer that is not allocated to an open file, preferably the last unallocated buffer in the chain of buffers. In accordance with the present invention, a buffer storage location can be allocated to multiple open files. De-allocation of a buffer storage location from an open file will not cause the buffer storage location to be moved to the beginning of the chain when the buffer storage location is allocated to one or more other open files. When data within a buffer storage location has been modified, prior to de-allocation of that buffer storage location with respect to an open file, the processor writes the data, including the modifications, back to the associated sector in mass memory. In one embodiment, the system of the present invention is incorporated in a portable electronic device including a keyboard and a display, and a housing for housing the keyboard, display, processor, buffer, and memory. In a preferred embodiment, the portable electronic device is a navigation aid and selected data is map data.