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System Power Control Network Code Download Mechanism

IP.com Disclosure Number: IPCOM000120572D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 6 page(s) / 252K

Publishing Venue

IBM

Related People

Berglund, NC: AUTHOR

Abstract

Each of the nodes of the power control network contain EEPROM storage to hold part of the node control code. This storage can be updated to add new function or correct design problems. The code for each node must be transferred across the serial power control network interface. The time to load all the network nodes can significantly add to the system IPL time.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 27% of the total text.

System Power Control Network Code Download Mechanism

      Each of the nodes of the power control network contain
EEPROM storage to hold part of the node control code.  This storage
can be updated to add new function or correct design problems.  The
code for each node must be transferred across the serial power
control network interface.  The time to load all the network nodes
can significantly add to the system IPL time.

      Described is a mechanism used to minimize the time to perform a
code download operation into the slave nodes.  The mechanism takes
advantage of the structure of the network, i.e., the point-to-point
connections from rack to slave, and the structure of the
command/response protocol to provide a simultaneous download into
multiple nodes.
POWER CONTROL NETWORK STRUCTURE

      The logical structure of a power control network from the
Central Electronics Complex (CEC) node to the slave nodes in each
rack is shown in Fig. 1.

      Communication between the CEC, rack and slave nodes uses a
command/response protocol.  A command is sent from the CEC node to
the selected destination.  No further commands will be sent until a
response has been received or a time interval has expired.  One
command may be sent to one destination or to multiple destinations
within one rack or in multiple racks.  The command is delivered to
each selected rack in physical order, i.e., the order of
interconnection, and to each unit in numerical order.  The command is
not forwarded to the next node until the current one has responded.
Each destination receiving a command is required to provide a
response (a rack which only passes the received command to a slave
within a rack or to the next rack does not provide a unique
response).  The responses are returned to the CEC in "physical
order", Unit 1 in Rack x, Unit 2 in Rack x, Unit n in Rack
x, Unit 1 in Rack y, etc.

      Fig. 2 contains an example of command/response flow for a
command addressed to all slaves in all racks.

      1.  The CEC initiates a slave broadcast command to all the
slaves in all racks.
     a.  Rack 1 receives the command and determines that the
         command is addressed to every slave in every rack.
     b.  Since there are no additional units in rack 1, rack
         1 builds a response and returns the response to the
         CEC node.
     c.  After returning the response, rack 1 forwards the
         command to the next rack.

      2.  Rack 2 receives the command and determines that the command
is
     addressed to every slave in every rack.
     a.  The rack node forwards the command to Unit 1.
     b.  Unit 1 executes the command and returns a response
         to the rack.
     c.  The rack node saves the response from Unit 1 and
         forwards the command to Unit 3.
     d.  Unit 3 executes the command and returns a response
     ...