Browse Prior Art Database

Method for Field-Upgrading a Server to a BMC from a DMC Disclosure Number: IPCOM000028736D
Original Publication Date: 2004-May-28
Included in the Prior Art Database: 2004-May-28
Document File: 2 page(s) / 154K

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Currently, our servers use a proprietary scheme for monitoring environmentals. We call this a drawer management controller (DMC). It is used in conjunction with a service processor (SP), to handle the systems management functions in our systems. We are trying to migrate from the DMC/SP structure to a structure where the DMC is replaced by an Intelligent Platform Management Interface (IPMI) compliant baseboard management controller (BMC). Since the BMC was not going to be available for product GA, we needed to develop a scheme that would allow the BMC to be plugged into the system without having to change system boards. This invention allows us to plug in the BMC by accomplishing the following four things. 1. It must automatically and completely disable the DMC (including shutting off its heartbeat LED) by merely be plugged in. 2. It must work without (or with) the SP. 3. It accommodates the additional hardware interconnects that the BMC requires but the DMC doesn't (serial ports, LPC bus, etc.). 4. It must fit in the space above the DMC on the system board using a very low profile connector.

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Method for Field-Upgrading a Server to a BMC from a DMC

     The solution was to incorporate a SO-DIMM 144 pin connector on the system planar. This solution allowed the IPMI BMC solution to be connected when it became available. We feel the SO-DIMM connector is an appropriate choice due to its relatively small form factor, low profile and high pin count. The SO-DIMM connector that we chose would allow the BMC to be inserted at an angle parallel to the board right above the DMC. The height of the SO-DIMM connector was appropriate because even with the proposed BMC riser card inserted parallel to the base planar, there was still enough clearance underneath the card for most components. This is important because we did not know the size of the BMC riser card (although we did set a limit) and to assign a large keepout region would compromise a lot of board real estate for placing components. The region below the BMC riser card would be used to place the DMC and its components (when the BMC is fully adopted, it will be simple to depopulated the DMC components and place the BMC components in this area.)

     We worked closely with the BMC developers to pinout the connector. Since the BMC is a replacement for the DMC, they have a lot of common signals. We also require that the DMC be disabled when the BMC is present. The solution was to have a presence detect signal from the BMC going to the system CPLD to disable the DMC when it is active. The CPLD will hold the DMC in reset whe...