Address offset feature for a hard disk drive

US6415383B1 · kind B1 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Dan Colegrove · معلمی نژاد, US
• Klaus Smolin · Mainz, DE
• Alfred Malina · Wolfstein, DE
• Martin Roosen · Hochheim, DE
• Kazuyuki Kobayashi · Yokohama, JP
• Masaki Kohno · San Jose, US

Key dates

• Filing date: Oct 6, 1999
• Grant date: Jul 2, 2002
• Expiry date: Oct 6, 2019

Classification

• Technology area (CPC G): Physics
• CPC primary: G06F9/441
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

A method of changing the operating system in a computer system by using an address offset mode (AOM) feature for the address space of a hard disk drive connected to the computer system. Initialization of the computer loads the first operating system (OS) from a user area in the disk drive address space. An enable AOM command offsets the disk drive address space and reinitializes the computer to load a second OS from a reserve space in the disk drive address space. A command setting the maximum size of the address space of the hard disk drive provides a wrap around feature allowing the entire address space of the disk drive to be addressable for diagnostics or updating purposes. The computer is returned to operation with the first OS by a disable AOM command, or alternatively, by a power on reset, a software reset or a hardware reset. The method of changing operating systems is coded in the hard disk drive and does not require additions or modifications to the memory or the BIOS ROM of the computer system.