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Method and Apparatus to detect fan errors reliably on a defective fan control logic

IP.com Disclosure Number: IPCOM000016161D
Original Publication Date: 2002-Nov-08
Included in the Prior Art Database: 2003-Jun-21
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Abstract

Disclosed is a method and apparatus for detecting fan errors reliably on a data processing system which has a defective fan control logic circuit. In the current scenario, fan errors are detected successfully if the fan control logic is working correctly. Fan control logic is a hardware circuit which makes fan run at a particular speed for cooling purpose in a data processing system. That means fans run at one speed with out any rapid fluctuations in the speed. A micro processor called service processor then determines fan errors. In order to do so service processor reads current speeds of all fans from fan sensors, checks whether a given fan has dropped below a predefined threshold value. Based on that service processor takes appropriate action of logging errors. This method, however, does not correctly identify fan errors if the fan speed is changing randomly due to a defective fan control logic. Incase fan control logic is defective there can be random voltage drops to fan and fan can keep on changing its speed rapidly. That makes it difficult to detect fan errors with existing methods.

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  Method and Apparatus to detect fan errors reliably on a defective fan control logic

Disclosed is a method and apparatus for detecting fan errors reliably on a data processing system which has a defective fan control logic circuit. In the current scenario, fan errors are detected successfully if the fan control logic is working correctly. Fan control logic is a hardware circuit which makes fan run at a particular speed for cooling purpose in a data processing system. That means fans run at one speed with out any rapid fluctuations in the speed. A micro processor called service processor then determines fan errors. In order to do so service processor reads current speeds of all fans from fan sensors, checks whether a given fan has dropped below a predefined threshold value. Based on that service processor takes appropriate action of logging errors. This method, however, does not correctly identify fan errors if the fan speed is changing randomly due to a defective fan control logic. Incase fan control logic is defective there can be random voltage drops to fan and fan can keep on changing its speed rapidly. That makes it difficult to detect fan errors with existing methods.

In the proposed method service processor reads current speed of a fan from fan sensor. It then checks whether or not speed for a given fan, in the data processing system, has dropped below a predefined threshold value. If a fan is running at normal speed then service processor puts a good mark on it. Incase fan is running below the threshold speed then service processor puts a bad mark for counting sequence of that fan. Service processor reads...