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agree,
e.g.,
OUTPUT specified against a read-only protection mode
indicator setting.
4.
There is a mismatch in riata set names for a data set involved in
a
volume switching operation.
This is discussed in the next section.
Volume switching
The
operating
system
end-of-volume
routine
does
password for a data set involved in
a
volume
switch.
protection is handled in the following ways:
not
request
a
Continuity
of
Input Data sets - Tape and Direct-Access Devices
Processing
continues if there is an equal cOffiparison between the
data set name in the tape label or DSCB on the volume
switched
to,
and
the
name of the data set opened with the password.
An unequal
comparison terminates processing.
output Data Sets - Tape Levices
The protection indicator in the tape label on the volume switched
to is tested.:
1.
If the protection indicator is
set
ON,
an
equal
comparison
between the data set name in the label and the name of the data
set opened with the password allows processing to continue.
An
unequal comparison results in a call for another volume.
2.
If the protection indicator is OFF, processing continues, and a
new label is written with the protection indicator set ON.
3.
If
only
a
volume
label
processing continues, and a
protection indicator set cn.
exists
on
new
label
output Data Sets - Direct-Access Devices
the volun,e switched to,
is
written
with
the
For
existing data sets, an equal comparison between the data set
name in a DSCB on the volume switched to, and the name of
the
data
set opened with the password allows processing to continue.
For new
output
data
sets,
the
mechanism
used to effect volume switching
ensures continuity of protection and the DSCB
created
on
the
new
volume will indicate protection.
Data Set Concatention
A password is requested for every protected data set that is involved
in
a
concatentation of data sets, regardless of whether the other data
sets involved are protected or not.
SCRATCH and RENAME Functions
An attempt to perform the SCRATCH or RENAME functions on a
protected
data
set results in a request for the password.
The protection feature
issues an operator's message when a protected data set is the object
of
these
functions.
The
Operator's Guide publication discusses the mes-
sage.
counter Maintenance
The operating system does not maintain the counter
in
the
password
record
and
no overflow indication will be given (overflow after 67,535
openings).
You must provide a counter maintenance routine to check and,
if
necessary, reset this counter.
114
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