IBM System/360 System Programmer's Guide

MAINTAINING THE CATALOG AND THE VOLUME TABLE OF CONTENTS
This chapter describes how to maintain and modify the catalog and the
volume table of contents through the use of macro-instructions. Most of
the maintenance and modification functions can also be performed using
utility statements. The utility statements are described in the
publication IBM System/360 Operating System: Utilities.
The functions you can perform using the macro-instructions are
described in text, and the formats of the macro-instructions are
tabulated on a fold-out sheet at the tack of this chapter. The chart on
the fold-out sheet associates the function described in text with the
macro-instructions needed to perform the function. You should keep the
fold-out sheet open when reading the text.
The functions that are described in text are as follows:
•
How to
read a block fron: the catalog.
•
How to build
an
index.
•
How to
build
a
generation index.
•
How
to delete an
index.
•
How to assign
an
alias.
•
How to
delete an alias.
•
How to
connect control
volumes.
•
How
to
disconnect control volumes.
•
How to catalog a data set.
•
How to rerr,ove
data set
references from the catalog.
•
How
to recatalog
a
data set.
•
How to
read a data
set control block from the volume table of
contents.
• How to delete a data set.
• How to rename a data set.
Accompanying the function descriptions in text are coding examples
and programm1ng notes; exceptional-return condition codes for the
macro-instructions are tabulated on the back of the fold-out sheet.
HOW TO READ A BLOCK FROM THB CATALOG
To read either an index block or a block indicating the volumes on
Which a data set is stored (volume-list block), you use the LOCATE and
CAMLST macro-instructions. There are two ways to specify the block that
you want read into main storage: by using the nawe of the index level or
data set, or by using the block's location relative to the beginning of
the catalog (TTR).
Specifying the Name of an Index Level or Data Set
If you specify an index level name, the first block of the named
index is read int,o main storage, and an exceptional return code is set.
Index tlock formats are contained in Appendix A of this chapter.
If you specify a data set name, a 256-byte volume-list block is read
into main storage. The block contains up to 20 volume pointers, each of
which points to a volume on which ~art of the data set is stored. The
first two bytes of the block contain the number of volume pointers for
the data set. Each volume pointer is a 12-byte field that contains a
4-byte device code, a 6-byte volume serial number, and a 2-byte data set
sequence number. (Device codes are contained in Appendix B of this
chapter.)
10

IBM System/360 Specifications

General

Brand	IBM
Model	System/360
Category	Desktop
Language	English