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Chaining in a Data Transfer Channel

IP.com Disclosure Number: IPCOM000036145D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Dixon, JD: AUTHOR [+6]

Abstract

This article describes a technique for use in a processor wherein a second set of channel control registers is provided, either set being able to control the channel, whereby the transfer channel is allowed to run at full speed continuously without having to wait for the processor to program it between individual transfers.

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Chaining in a Data Transfer Channel

This article describes a technique for use in a processor wherein a second set of channel control registers is provided, either set being able to control the channel, whereby the transfer channel is allowed to run at full speed continuously without having to wait for the processor to program it between individual transfers.

With any programmable hardware, there is a time spent programming the operation, and a time spent actually performing it. Usually, the time spent programming is not insignificant. Depending on the type of processor and the complexity of the operation, the time could be as much as the time spent by the hardware in doing the operation. The time spent in performing the operation is necessary, and cannot be removed. In this disclosure, the hardware is a data transfer channel between an adapter card and a personal computer system MICRO CHANNEL*.

To solve the programming latency problem, a new kind of channel is implemented. This channel has two sets of channel pointers and counters and can run on either set. When one set is running, the other is idle. When the active set is finished, the channel will automatically switch to the other, if it has been programmed up. While one side is active, the idle set of registers can be programmed for the next transfer. These will start as soon as the current operation in the active side is finished. With this method, the time to program the channel is not reduced, but it can b...