Browse Prior Art Database

Common H/W Structure of Local and Remote S/370 Channel Adapter

IP.com Disclosure Number: IPCOM000110398D
Original Publication Date: 1992-Nov-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 4 page(s) / 131K

Publishing Venue

IBM

Related People

Mizukoshi, Y: AUTHOR

Abstract

Disclosed is a common hardware structure design of two kinds of channel adapter, one is attached to the host processor's channel and another is attached to I/O control units. Microcode interface of both adapters consists of the same hardware resources and is defined, relatively, as mirror image. Implementation by using programmable logic devices solves the differences of both adapters, and it achieves flexibility without down performance.

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Common H/W Structure of Local and Remote S/370 Channel Adapter

       Disclosed is a common hardware structure design of two
kinds of channel adapter, one is attached to the host processor's
channel and another is attached to I/O control units.  Microcode
interface of both adapters consists of the same hardware resources
and is defined, relatively, as mirror image.  Implementation by using
programmable logic devices solves the differences of both adapters,
and it achieves flexibility without down performance.

      For channel extend mechanism, a conventional method is carrying
channel interface signal itself on serial high speed media.  But this
method has limitation of extend distance that is caused by
transmission signal delay.  Applying any new method to solve the
limitation, those channel adapters must have the functional
capability of responding or performing the channel interface
sequences by themselves.  The adapter attached to host processor's
channel, hereafter called local channel adapter, responds like an I/O
control unit.  The adapter attached to I/O control units, hereafter
called remote channel adapter, performs like the channel.

      Fig. 1 shows the common layer structure of both local and
remote channel adapter.  The common microcode interface of both
adapters is mainly following subsequent level interrupts and
commands.
o  ISS (Initial Selection Sequence)
o  DTS (Data Transfer Sequence)
o  ES (Ending Sequence)
o  CUIS (Control Unit Initiate Sequence)
o  RSTs (reset sequences: System Reset, Selective Reset, Interface
Disconnect)

      Fig. 2 shows a normal tag sequence, data flow and control
points of both local and remote channel adapter....