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Command Protocols for Remote System I/O Interface

IP.com Disclosure Number: IPCOM000109419D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 4 page(s) / 150K

Publishing Venue

IBM

Related People

Arndt, RL: AUTHOR [+4]

Abstract

The Remote System Interface (RSI) architecture provides a high performance mechanism for attachment of a wide variety of I/O devices to a processor. RSI defines a private, direct serial connection between a processor and its I/O subsystem (Fig. 1). It also supports processor to processor interconnections (Fig. 2), as well as attachment of more than one I/O Controller to a single serial link.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Command Protocols for Remote System I/O Interface

       The Remote System Interface (RSI) architecture provides a
high performance mechanism for attachment of a wide variety of I/O
devices to a processor.  RSI defines a private, direct serial
connection between a processor and its I/O subsystem (Fig. 1).  It
also supports processor to processor interconnections (Fig. 2), as
well as attachment of more than one I/O Controller to a single serial
link.

      Basically, RSI accepts a DMA or PIO command on the parallel
system I/O bus, converts it to a serial form, transmits that form to
a remote RSI unit which converts the command into a parallel command
on a remote system I/O bus.  Commands and data may be bidirectional,
and multiple operations may be interleaved or multiplexed on the
serial link.

      RSI is designed to support the movement of data and control
information within a wide variety of operational environments.  RSI
supports three basic functions to move data and control information
between a local processor and remote I/O Controllers.
      1.  PIO - The RSI architecture supports programmed I/O (PIO)
through the transmissin and reception of Load and Store commands.
      2.  DMA - The RSI architecture supports the basic Direct Memory
Access (DMA) transfer between an I/O adapter and main storage.
      3.  DMA initiate - The RSI architecture provides a means to
initiate a DMA transfer within the RSI facility.

      The RSI architecture may be implemented in a special-purpose
serial link using fiber-optic or electrical transmitter/receiver
pairs.  The link consists of a pair of media, one outbound and one
inbound.  The RSI architecture could also be implemented using the
Fibre Channel Physical and Signaling Interface (FC-PH) being
developed by an ANSI X3T9.3 Working Group where serial speeds of one
gigabit per second are specified.

      The following facilities and functions are desired:
      1.  DMA channel identification.
      2.  Frame sequence counts.
      3.  End to end flow control (dynamic pacing).
      4.  Multiple Start_of_Frame delimiters (initiate and
          passive).
      5.  End_of_Frame abort.
      6.  Ability to res...