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Broadcast Polling Procedure for Remote Data Interface

IP.com Disclosure Number: IPCOM000084206D
Original Publication Date: 1975-Oct-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

George, DA: AUTHOR [+2]

Abstract

This polling procedure acts independently and almost concurrently for each Remote Data Interface (RDI) line. Instead of continuously polling, this procedure operates on two interrupt levels of which one is higher than the disk and supervisor levels while the other is higher than only user application code. A carrier detect signal line is available in each Modem (MOD) 10 of the interface of controller 11. The broadcast poll for RDI lines is as follows: 1. Delay x amount of time (assume x - 25 ms). 2. Reset flip-flop (FF) 12. 3. Send broadcast poll message to all terminals 13 on RDI line. 4. Wait W amount of time (W>time to travel to and from longest distance plus MODEM turnaround time). 5. Examine FF 12, if reset go to step 1 and repeat; otherwise go to next step. 6.

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Broadcast Polling Procedure for Remote Data Interface

This polling procedure acts independently and almost concurrently for each Remote Data Interface (RDI) line. Instead of continuously polling, this procedure operates on two interrupt levels of which one is higher than the disk and supervisor levels while the other is higher than only user application code. A carrier detect signal line is available in each Modem (MOD) 10 of the interface of controller 11. The broadcast poll for RDI lines is as follows: 1. Delay x amount of time (assume x - 25 ms). 2. Reset flip-flop (FF) 12. 3. Send broadcast poll message to all terminals 13 on RDI line. 4. Wait W amount of time (W>time to travel to and from longest distance plus MODEM turnaround time). 5. Examine FF 12, if reset go to step 1 and repeat; otherwise go to next step. 6. Terminal responds to broadcast poll with device number only, thus controller 11 knows who to poll. If more than one terminal 13 responded to the broadcast poll, then if no complete terminal address was received, a sequenced poll is initiated by controller 11 through MODEM 10. The sequenced poll begins with the terminal 13 next on the poll list after the last terminal polled, unless part of a terminal address was received by the broadcast poll. If NNNxxx were received for an address where x means lost character, then the sequenced poll begins with address NNN000. Polling continues until a hit is made. 7. After a hit, to to step 2 and repeat. If term...