Browse Prior Art Database

Single List for Programmed Poll and Autopoll

IP.com Disclosure Number: IPCOM000073482D
Original Publication Date: 1970-Dec-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Siegel, JJ: AUTHOR

Abstract

One of the elements of a terminal control system is the systematic solicitation of messages from the terminals. Autopoll has enabled support of larger systems by eliminating negative response interrupts and the associated program handling. The table or "polling list" required for autopoll is different from that originally used by BTAM and QTAM, thereby requiring two different polling lists and associated logic.

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Single List for Programmed Poll and Autopoll

One of the elements of a terminal control system is the systematic solicitation of messages from the terminals. Autopoll has enabled support of larger systems by eliminating negative response interrupts and the associated program handling. The table or "polling list" required for autopoll is different from that originally used by BTAM and QTAM, thereby requiring two different polling lists and associated logic.

In a system with different terminal types or applications, control information must be maintained for each terminal. When programmed poll is being used, a pointer to the terminal dependent information can be saved before the poll is initiated and later retrieved if that poll results in a message. With autopoll, the responding terminal cannot be determined prior to the poll.

A single polling list can be used to autopoll or program poll terminals on a multipoint line by using the format on an autopoll list indicated in Drawing A.

The index bytes then reference either another list or an appendage to the actual polling list and that list references the actual terminal table entry as in Drawing B.

If autopoll is used with the above list, the index byte stored by the autopoll feature is used to calculate a terminal table entry that identifies the terminal responding. Assuming two byte relative addresses, the index byte is doubled and subtracted from the list address.

If programmed poll is used, the address of the poll...