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Note:
For
output data sets, the system uses the contents of the block
count (BLKCT) field to write the block count in trailer labels when
the
data
control
block
is
closed,
or
when the EOV macro-instruction is
issued.
You must maintain the contents of this field
yourself
if
the
system is to write the correct block count.
Device
dependent
portion
of
data
control
block when DEVD=PT and
DSORG=PS:
DCB
r------T----------------------,
Address +16 ICODE
I
Reserved
I
L ______
~
______________________ J
Device dependent portion of
data
control
block
when
DEVD=PR
and
DSORG=PS:
DCB
r------T----------------------,
Address +16 IPRTSP I
Reserved
I
L ______ L __________ - ___________ J
Device
dependE~nt
portion of data control block when DEVD=PC or RD and
DSORG=PS:
DCB
r-----------T-----------------,
Address +16 IMODE,STACK
I
Reserved
I
L ___________
~
_________________
J
The
following
parameters
pertain
to
specific
devices and may be
specified only when the DEVD parameter is specified.
KEYLEN=value
specifies, for direct-access devices, the length in bytes of the
The following parameters pertain
to
specific
devices
and
may
be
specified only when the DEVD parameter is specified.
KEYLEN=value
specifies,
for
direct-access
devices, the length in bytes of the
key of a physical record, with a maximum
value
of
255.
When
a
block
is
read
or written, the number of bytes transmitted is the
key length plus the record length.
CODE=value
specifies, for paper tape, the code in which records are punched as
follows:
Value
I
F
B
C
A
T
N
IBM BCD
Friden
Burroughs
National Cash Register
ASCII
Teletype
no conversion
(forrrat F records
only)
If this parameter is omitted, N is assumed.
DEN=value
specifies, for magnetic tape, the tape recording
density
in
bits
per inch as follows:
Execute Channel Program (EXCP) Macro-Instruction
89
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