Browse Prior Art Database

Single System Image

IP.com Disclosure Number: IPCOM000109253D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Badaoui, M: AUTHOR [+4]

Abstract

Disclosed is an implementation which allows interfacing a remote Data Bank from two computers with the same address using only one switched network modem.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 89% of the total text.

Single System Image

       Disclosed is an implementation which allows interfacing a
remote Data Bank from two computers with the same address using only
one switched network modem.

      Existing Fan Out boxes allow interfacing two, or more,
computers via a leased line modem.  Those boxes do not provide
switched network access.

      The proposed implementation solves switched network access and
uses the same address for the two computers.
      1. Switched Network Access Solution.

      Fan Out boxes logic must be modified at Data Terminal Ready
level and Ring Indicator level.
      a. Data Terminal Ready (DTR) change.

      DTR is raised by the computer which means Computer Ready to
Transmit or Receive.

      DTR is coming from both Computers: DTR1 from Computer 1 and
DTR2 from Computer 2.  An OR logic function has to be added at Fan
Out box level to have DTR1 OR DTR2 sent to DTR received input modem.
      b. Ring Indicator (RI).

      RI is coming from switched network modem.

      RI has to be sent to both computers, so as with DTR, an OR
function has to be added at Fan Out box level to send RI1 to computer
1 and RI2 to computer 2.
      2. Computer 1 and 2 same address.

      Computer 1 uses a BSC protocol and Computer 2 uses an SDLC
protocol.

      Upon receiving RI1 and RI2, Computer 1 and 2 wait for address
recognition.  The address is recognized by the computer in compliance
with the Transmi...