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IMPLEMENTING DATA SET PROTECTION
To
prepare
for
use
of
the
data
set
protection
feature of the
operating system, you place a sequential data set,
named
PASSWORD,
on
the
system residence volume.
This data set must contain one record for
each data set placed under protection.
In turn, each record contains
a
data
set
name,
the
password
for
that
data set, a counter field, a
protection wode indicator, and a field for recording any information you
desire to log.
On
the
system
residence
volumei
these
records
are
formatted as a "key area" (data set name and password) and a "data area"
(counter field, protection mode indicator, and logging field).
The data
set is searched on the "key area."
You must write routines to create and maintain the PASSWORD data set.
These routines may be placed in your own litrary or the system's linkage
editor
library
(SYS1.LINKLIB).
You
may use a data management access
method or EXCP programming to handle the PASSWORD data set.
If a data set is to be
placed
under
protection,
it
must
have
a
protection
indicator
set
in
its lacel (DSCB or header 1 tape label).
This is done by the operating system when the data set is created.
The
protection
indicator
is
set
in
response
to
an entry in the LABEL=
Darameter of the DD statement associated with the data set being
placed
under
protection.
The
Job Control
Lan~
publication describes the
entry Note: Data sets on magnetic tape are protected only when
standard
labels are used.
The
balance
of this chapter discusses the PASSWORD data set charac-
-teristics and record format, the creation of protected
data
sets,
and
operating characteristics of the data set protection feature.
PASSWORD DATA SET CHARACTERISTICS AND RECORD FORMAT
The
PASSWORD
data
set
ITust
reside
en
the
same
voluwe as your
operating system.
The space you allocate to the PASSWORD data set
must
be contiguous, i.e., its DSCB must indicate only one extent.
The amount
of
space
you
allocate
is
dependent
on the number of data sets your
installation desires to place under protection.
The organization of the
PASSWORD data set is physical sequential, and the content
is
unblocked
format-F
records,
132
bytes in length (key area plus data area).
The
following illustration shows the password records
as
you
would
build
them
in
a
132
byte work area.
Explanation of the fields follows the
illustration.
"
~52
byte
"key"
.
80 byte 'data area
~
44 bytes
-
8
.-
/3 bytes
77 bytes
..
~
....
bytes
fully qualified
pass-
logging field
data set name
word
(optional informa-
tion)
j~ ~
•
mode indi-
protect10n
cator - ] byte
' - - - - -
b1nary counter
-
b
2
yte s
The name of the protected data set
being
opened
and
the
password
entered by the operator are watched against the 52-byte "key area."
The
112
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