Browse Prior Art Database

Distributed Portable Operating System Interface Teletypewriter Support on Proprietary Multi-Processor Based Systems

IP.com Disclosure Number: IPCOM000113262D
Original Publication Date: 1994-Jul-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 4 page(s) / 97K

Publishing Venue

IBM

Related People

Clausen, TL: AUTHOR [+6]

Abstract

Disclosed is a solution to distribute Portable Operating System Interface (POSIX) teletypewriter (TTY) support between a primary and secondary processor (i.e., a distributed function environment versus the typical single processor UNIX* style environment). The key problem being solved is the integration of a 'tightly-coupled' terminal-to-application environment on a 'loosely-coupled', "many" processor system environment and the coexistence between environments.

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

Distributed Portable Operating System Interface Teletypewriter Support
on Proprietary Multi-Processor Based Systems

      Disclosed is a solution to distribute Portable Operating System
Interface (POSIX) teletypewriter (TTY) support between a primary and
secondary processor (i.e., a distributed function environment versus
the typical single processor UNIX* style environment).  The key
problem being solved is the integration of a 'tightly-coupled'
terminal-to-application environment on a 'loosely-coupled', "many"
processor system environment and the coexistence between
environments.

Key element details involved in a 'working solution' include:

1.  Unique 'logical host connection' for POSIX support between the
   'primary' host processor and the 'secondary' I/O processor.  In
   addition, the connection is designed such that it provides the
   following characteristics:
   a.  Asynchronous data transfers
   b.  Multi-plexing of commands for all devices into single 'Data
       Packets' (to reduce system bus utilization and host task
       switching)
   c.  Minimum IOP data transmission initiation 'time intervals' of
       multiplexed data packets
   d.  'Initiator' data transfer 'throttling mechanism' to control
       receiving processor 'buffer allocation' over-runs and at the
       same time ensuring maximum utilization of available buffers
       o   based on IOP activation sequence defined 'maximum
           available buffer byte count' (on a device basis) and
           communication on the asynchronous Data transfers of the
           'last character count processed' and 'last character sent
           count'
       o   the sending processor only sends when the 'known'
           difference in the character count values is less than the
           known 'maximum available buffer...