Browse Prior Art Database

Save Modification of ESCD's

IP.com Disclosure Number: IPCOM000011754D
Original Publication Date: 2003-Mar-12
Included in the Prior Art Database: 2003-Mar-12
Document File: 1 page(s) / 37K

Publishing Venue

IBM

Abstract

Because most BIOS's need some form of NVRAM , these BIOS's have implemented the ESCD architecture which stores data in the Flash . On current Flash modules, the Flash is segmented in 64K segments and the ESCD take a whole 64K segment. To modify a single entry in the ESCD, all 64K of the Flash must be cleared prior to writing the segment. On a 512K Flash (the most popular Flash size), this means that 12.5% of the Flash is dedicated to this function. Flash vendors have resisted making their segmentation smaller since the part will become more expensive. In the Past, as the Flash fills up with new functions, code is moved into this segment. This creates a problem when the system is power off during the update process. Since code is now lost, the planar becomes corrupted and must be boot blocked to recover. This process is not customer friendly or acceptable.

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Save Modification of ESCD's

      We propose to utilize the PARTIES area (as define in the ANSI specification) as a scratch pad for ESCD. First, the ESCD structures could be moved onto the hard file (PARTIES). Since we believe this will increase boot times (waiting for hard file spin up), this was not considered a viable option. The more viable solution was to use the PARTIES space to hold a spare copy of the code in the ESCD segment. When a system is flashed, a copy of the code in the ESCD segment is copied to the PARTIES space. If the ESCD segment is later corrupted during an ESCD update, the BIOS will look into the PARTIES space for code that should occupy the ESCD segment. This code could then be used to rebuild the segment. Using this method, the ESCD segment can be recovered without forcing a manual recovery. This saves the desktop group from adding a bigger Flash module which is a more expensive solution.

Disclosed by International Business Machines Corporation

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