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Noninitialized Intelligent Terminal Controller State

IP.com Disclosure Number: IPCOM000087130D
Original Publication Date: 1976-Dec-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Cannistra, T: AUTHOR [+6]

Abstract

It is desirable to define a noninitialized state in which an intelligent controller can exist to permit the controller's communication program to be paged out to a disc during periods of time when data is not being transferred to a host computer. This state reduces memory requirements at the controller while still allowing complex data processing to be performed at the controller. The noninitialized state can be communicated to the computer access method program by a combination of sense bits.

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Noninitialized Intelligent Terminal Controller State

It is desirable to define a noninitialized state in which an intelligent controller can exist to permit the controller's communication program to be paged out to a disc during periods of time when data is not being transferred to a host computer. This state reduces memory requirements at the controller while still allowing complex data processing to be performed at the controller. The noninitialized state can be communicated to the computer access method program by a combination of sense bits.

All commands from the computer except Test I/O, Halt I/O, Sense, Sense ID, and the Initialization Control command will be rejected by the controller with a unit check status bit when the controller is in the noninitialized state. Those commands which are accepted allow initialization and diagnostic programs to be run. The initialization control command provides initialization parameters, such as (1) the number of host computer buffers available per start I/O command, (2) the size of those buffers, and (3) the access method programs link ready size, and causes the controller to load its communication program module from disk.

The noninitialized state can also be used to advantage when an unrecoverable error has occurred and termination of the on-line connection by the host computer is imminent. Under these conditions, the controller can count message retry communications from the host computer and place itself in the nonin...