Browse Prior Art Database

Recovering Buffered Data

IP.com Disclosure Number: IPCOM000050726D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Robinson, FL: AUTHOR [+2]

Abstract

A peripheral storage system has a buffer for containing data to be furnished to a host and data received from a host for recording onto a recorder. The recorder sends a ready signal when it is available for recording signals on a record medium. It can send a ready to not ready interrupt to a control for the buffer. Men the buffer has data to be recorded in the record medium, the control immediately sends an interruption signal to the host. The host will then attempt to select the recorder, whereupon the control signals a unit check error condition with an indication that there is data in the buffer that was not successfully recorded. The host then responds to recover data from the buffer, thereby simplifying error recovery procedures.

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Recovering Buffered Data

A peripheral storage system has a buffer for containing data to be furnished to a host and data received from a host for recording onto a recorder. The recorder sends a ready signal when it is available for recording signals on a record medium. It can send a ready to not ready interrupt to a control for the buffer. Men the buffer has data to be recorded in the record medium, the control immediately sends an interruption signal to the host. The host will then attempt to select the recorder, whereupon the control signals a unit check error condition with an indication that there is data in the buffer that was not successfully recorded. The host then responds to recover data from the buffer, thereby simplifying error recovery procedures.

The host communicates to the recorder via an I/O interconnection to a buffer. The buffer then relays the data over a device control interconnection (DCI) to the recorder. A control is in communication with the host and recorder and buffer for coordinating the data transfers. Often a recorder will have a removable record medium (RM), such as a spool of magnetically-coded recording tape. Removing the record medium or tape from the recorder causes it to go from a ready to not ready state. Other changes in status may also cause a ready to not ready state change. The recorder then sends at (1) a ready to not ready interruption signal to the control. The control responds to the interruption signal to sense whether or not the buffer has data to be recorded on the record medium. Since the recorder is not ready, there is no guarantee that the data in the buffer will ever be recorded on the record medium. Ac...