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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.)
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