Browse Prior Art Database

Distributed Message Processing Capability in a Teleprocessing Subsystem

IP.com Disclosure Number: IPCOM000080630D
Original Publication Date: 1974-Jan-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 4 page(s) / 44K

Publishing Venue

IBM

Related People

Herman, TD: AUTHOR [+2]

Abstract

This description relates to a teleprocessing subsystem, which makes effective use of large-scale integration (LSI) techniques in the implementation of the subsystem.

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Distributed Message Processing Capability in a Teleprocessing Subsystem

This description relates to a teleprocessing subsystem, which makes effective use of large-scale integration (LSI) techniques in the implementation of the subsystem.

The system shown here consists of a Line Framing Unit which interfaces to the communication line and its discipline. This Line Framing Unit has the following functions:
1) The capability to serialize and deserialize characters

from the line, based on a prescribed number of bits

per character.
2) A design that is transparent in nature, in that it

basically frames characters from the line so that they

can be forwarded to the local subsystem.
3) The Line Framing Unit has full duplex capability.

It can receive characters from the line which will

be referred to as output characters and/or messages,

and also has the capability to serialize or transmit

characters to another line which will be referred to

as an Input line. Input and Output terminology is

with respect to a host processor system, supporting

the subsystem via the communications line and an

appropriate line discipline.
4) The Line Framing Unit has the responsibility to recognize

sync or framing characters.
5) It has the responsibility to generate check characters

for transmission on input messages as well as deciphering

receive check characters, to determine whether or not

any errors were encountered in the output message

transmission. Thus, the overall function of the Line

Framing Unit is to assemble characters for distribution

within the subsystem to the various devices attached to

the subsystem, and to forward characters from the subsystem

to the host system.

Attached to the Line Framing Unit within the subsystem is what will be called a Line Synchronous Serial Loop. This loop is synchronized at the baud rate of the communication line. The Line Framing Unit performs the following functions in controlling the Line Synchronous Serial Loop:
1) Sends out Broadcast messages on the loop.
2) Polls devices on the loop, to determine whether or

not they have messages for transmission into the

host processor.
3) Sends out Control messages on the loop, to prepare

the devices for message transmission or reception.

One of the salient features of the Loop discipline is the fact that the Line Framing Unit can communicate with devices on the loop, but is insensitive to the number of devices on the loop or the address of the specific devices. This will be

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illustrated later in an example. The devices on the loop are designed such that they are a ROS (Read-Only Storage) controlled set of hardware that has common characteristics, and it is the final characterization of the ROS or program portion of that particular device, which makes the final reconciliation of the host-line discipline with the particular device discipline. It should be noted that by definition, the host line can only talk to or receive messages from one device at a time, and the...