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Method for RSSM Media Tray Presence detection in a Blade Center S Ecosystem

IP.com Disclosure Number: IPCOM000199555D
Publication Date: 2010-Sep-09
Document File: 2 page(s) / 31K

Publishing Venue

The IP.com Prior Art Database

Abstract

The media tray in the BCS chassis is a customer replaceable unit which contains the optical media drive, two (2) USB ports, up to two (2) BBUs, and RSSM system persistent data. Within the BC-S chassis, the AMM is currently the only device that is designed for presence detection of the Media Tray. Media tray presence is significant to the RSSM, due to the fact that it contains a piece of RSSM system persistent data. Without having the media tray, the RSSM is missing one of the quorum devices for VPD synchronization. With the current BC-S chassis design there is no mechanism to query the AMM in the ecosystem to establish whether or not the media tray exists. With the current design an imprecise assumption is made that if a failure to communicate with the media tray and the BBUs, it is assumed that the MT is removed, however, this may not always be the appropriate assumption. Another issue is that there is no current design point for detecting that the media tray was swapped or removed and reinserted during a polling interval. This can potentially cause VPD synchronization issues and can also limit the ability to due concurrent repair operations.

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Method for RSSM Media Tray Presence detection in a Blade Center S Ecosystem

0.1.1 Presence Detection

The BMC performs the function to gather status about whether the media tray is present in the system. The BMC performs the following functions:

• If this BMC is the Master or the only BMC present (i.e. single controller operation) then it will perform the presence detection.

• Add to the BMC's normal scan loop to scan for the Media tray.
• In a dual controller configuration, if the BMC cannot determine a Master BMC (i.e. it is unable to communicate with the alternate BMC to establish a Master) then BMC media tray presence detection is disabled.

• The Master BMC will:

o Check BBU presence, if BBU is present, then by default the Media Tray is

considered present. This resets the current not-

present count to zero (0). If the

previous state was not present, then this will trigger a state transition update to

SES.

o If BBUs are not present,

o If the READ is successful, the Media Tray is considered present. This resets the

current not-

present count to zero (0). If the previous state was not present, then

this will trigger a state transition update to SES.

o If the READ fails and the state is present, increment a failure count.

If the not-

present count increments to three (3), then the media tray is

considered to be not present. If the previous state was present, then this will trigger a state transition update to SES.

0.1.2 Polling Interval

The BMC will perform presence detection for the media tray such that an update to the state information would be available to the SES device approximate...