Browse Prior Art Database

Micro Channel File Multiplexer

IP.com Disclosure Number: IPCOM000099743D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Fasig, JL: AUTHOR

Abstract

The figure illustrates a MICRO CHANNEL* file multi- plexer that permits a simultaneous connection of up to eight direct-bus-attach hard files to a MICRO CHANNEL. In the past, an implementation used was to hardwire a primary and a secondary address in a file adapter, and all direct-bus-attach files have the same primary and secondary addresses. With only two possible address assignments, one is limited to a maximum of two files per computer system. The described MICRO CHANNEL file multiplexer overcomes this two-file limitation and demonstrates a simple way to facilitate the connection of up to eight files at a time.

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This is the abbreviated version, containing approximately 59% of the total text.

Micro Channel File Multiplexer

       The figure illustrates a MICRO CHANNEL* file multi-
plexer that permits a simultaneous connection of up to eight
direct-bus-attach hard files to a MICRO CHANNEL.  In the past, an
implementation used was to hardwire a primary and a secondary address
in a file adapter, and all direct-bus-attach files have the same
primary and secondary addresses.  With only two possible address
assignments, one is limited to a maximum of two files per computer
system. The described MICRO CHANNEL file multiplexer overcomes this
two-file limitation and demonstrates a simple way to facilitate the
connection of up to eight files at a time.

      The MICRO CHANNEL is used on a motherboard in a test system
which connects to a PS/2* MICRO CHANNEL via an adapter card and
extends to the MICRO CHANNEL bus by several feet using cables.  In
addition, it provides a multiplexing mechanism whereby up to eight
hard files are attached to the channel at one time.  This test system
brings the microprocessor bus out of a system box and provides a
simple means of attaching more adapters.

      MICRO CHANNEL-compatible files transfer information to and from
the channel in two modes.  One mode is as an I/O device for commands
and status, and the other mode is as a DMA-Slave device for data.  In
both modes, the file accepts or presents information only on bus
cycles when its I/O address, card select signal, or Arbitration ID
are valid and the bus signal IO i...