Pseudo Dynamic Attachment of Serial Parallel Protocol Converters Through A Dynamic Fiber-Optic Switch

Pseudo Dynamic Attachment of Serial Parallel Protocol Converters
Through A Dynamic Fiber-Optic Switch

      All control units attached to a channel can be supported
by modifying converter protocols to support disconnects through a
serial switch.

      Converter design would be additionally modified by adding an
allegiance register per control unit.  The purpose of the allegiance
register is to provide the proper pathing information for both
solicited (like reconnect for command chaining or split device end)
or unsolicited (like not ready to ready status) reconnect requests
from the control unit.

      The problem from the channel side is the direction of system
reset.  There are several possible solutions, two of which will be
discussed here; either of which will work. The first would be to
restrict all the control units on a single converter to a single
channel, this solution is easy to implement, but limits the
connectivity.  The other solution is to use the allegiance register
to direct the system reset via a selective reset to the control units
that have allegiance to a particular channel.

      The configuration control program must be aware of these
allegiance registers and must be able to modify them to affect
configuration changes.  This is accomplished by having the converter
design recognize a special frame that is to be routed to the internal
control function of the converter.  This frame is sent for each of
the allegiance registers.

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