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Asynchronous Document Transmission Setup To Facilitate Error Recovery

IP.com Disclosure Number: IPCOM000048501D
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 3 page(s) / 16K

Publishing Venue

IBM

Related People

Busch, DG: AUTHOR [+2]

Abstract

Word processing systems can be used to create and transmit documents to remote terminals or CPUs (central processing units). One advantage of off-line document creation is the availability of word processing functions, such as automatinc margin text and page number insertion. A document containing complex text processing controls can be formatted and transmitted to low level data processing terminals or to CPU host programs. Another advantage is a reduction in communication line and computer connect charges. Document transmission, while more efficient via the synchronous protocols, may be done using one of the asynchronous (start-stop) protocols in order to communicate with the large set of existing asynchronous (ASYNC) machines and programs.

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Asynchronous Document Transmission Setup To Facilitate Error Recovery

Word processing systems can be used to create and transmit documents to remote terminals or CPUs (central processing units). One advantage of off-line document creation is the availability of word processing functions, such as automatinc margin text and page number insertion. A document containing complex text processing controls can be formatted and transmitted to low level data processing terminals or to CPU host programs. Another advantage is a reduction in communication line and computer connect charges. Document transmission, while more efficient via the synchronous protocols, may be done using one of the asynchronous (start-stop) protocols in order to communicate with the large set of existing asynchronous (ASYNC) machines and programs.

Because the start-stop protocols have no mechanism for detecting line errors and automatically retransmitting data, operator intervention is required for error recovery. Interactive host applications handle receive data parity errors by requesting that the operator resend the erroneously received line of data. In some asynchronous systems, the operator is restricted to the transmission of an entire document. If a CPU requests retransmission of a line, such systems will have to terminate the operation in progress and resend the entire document with the risk that another erroneous line will occur during the retransmission. Such solutions are inflexible, and potentially waste considerable operator time and communication line charges.

The following approaches should go a long way to solving error recovery problems that an operator might encounter during document transmission:
1. Allow the operator control of what is sent; for example,

allow the operator to easily specify transmission of an

entire document, or a range of pages within a document

and even a starting line number.
2. Provide the operator with status information, that is,

the document name, the current page, and the current

line number being sent.
3. Provide an easy mechanism for stopping the document

transmission, and the capability to scroll back the

screen in order to read any host message that might

have been received.
4. Provide an easy mechanism for resuming document transmission.

For example, provide default document, page, and line number

information, such that the transmission can resume on the line

that was previously being sent.

In the following communicating display word processor, an asynchronous communication feature allows the transmission of documents stored on diskettes as follows:

Starting Document Transmission:

Sending from a document is initiated by depressing the Document Send ON/OFF key. The current status is posted on the Session Header line on the display: as "Document Send: ON" or "Document Send: OFF" When

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the Document Send key is initially depressed, its status indicator is changed from "OFF" to "ON" and the following prompt is...