Browse Prior Art Database

DFDSS COPY With VTOC Adjustment

IP.com Disclosure Number: IPCOM000036558D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Chico, JH: AUTHOR [+2]

Abstract

This invention pertains to the full-volume COPY function of Data Facility Data Set Services (DFDSS). The full-volume COPY function is enhanced to copy the source volume table of contents (VTOC) to a predefined VTOC on the receiving volume while preserving the target VTOC location and its size. This predefined VTOC must be larger than the source VTOC and must reside after the last track of the source volume. The latter is to ensure that the resulting VTOC will not be overwritten with the source data tracks.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

DFDSS COPY With VTOC Adjustment

This invention pertains to the full-volume COPY function of Data Facility Data Set Services (DFDSS). The full-volume COPY function is enhanced to copy the source volume table of contents (VTOC) to a predefined VTOC on the receiving volume while preserving the target VTOC location and its size. This predefined VTOC must be larger than the source VTOC and must reside after the last track of the source volume. The latter is to ensure that the resulting VTOC will not be overwritten with the source data tracks.

Since the data set control blocks in the VTOC are chained by physical track addresses (cylinder:head:record), these pointers are updated during the COPY function to reflect the new location and to preserve the access protocols.

Referring to the figure, the method of the invention for COPY with VTOC adjustment comprises the steps of: (1) recognizing the location and size of the VTOC on

both the source and target volumes,

(2) determining the method of copying the VTOC;

(a) if the VTOC on the target volume is larger

than the VTOC on the source volume and it is

outside the range of the source volume, then

copy the source VTOC to the target VTOC while

preserving the target VTOC location, size,

and access protocols; otherwise,

(b) copy the source VTOC to the same physical

track location on the target volume, and

(3) copying the remaining data tracks.

1

Page 2 of 2

2

[This page contains 3 pictures or other non-text objects]