EasyManuals Logo

IBM System/360 System Programmer's Guide

IBM System/360
137 pages
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Page #102 background imageLoading...
Page #102 background image
dcb-addr
R -
Read
a
block.
W -
Write
a
block.
V -
Verify
contents
of
a
block
but
do
I -
Locate
a
block
by
identification.
present,
and
the
data
portion
written.
)
K -
Locate
a
block
by
key.
(Only
the
block
is
read
or
written.)
not
transfer
data.
(The
key
portion,
if
of
the
block
are
read
or
data
portion
of
the
specifies
the
address
of
the
data
control
tlock
of
the
data
set.
area-addr
specifies
the
address
of
an
input
or
output
area
for
a
block
of
the
data
set.
length-value
specifies
the
number
of
bytes
to
be
transferred
to
or
from
the
input
or
output
area.
If
blocks
are
to
be
located
by
identifi-
cation
and
the
data
set
contains
keys,
the
value
must
include
the
length
of
the
key.
The
maximum
number
of
bytes
transferred
is
32767.
key-ador
specifies,
when
blocks
are
to
be
located
by
key,
the
address
of
a
main
storage
field
that
contains
the
key
of
a
block
to
be
read
or
overwritten.
keylength-value
specifies,
when
blocks
are
to
be
located
by
key,
the
length
of
the
key.
The
maximum
length
is
255
tytes.
blkref-addr
specifies
the
address
of
a
main
storage
field
containing
the
actual
device
addrless
of
the
track
containing
the
1::lock
to
be
located.
When
blocks
are
to
be
located
by
key,
this
field
is
seven
bytes
in
length;
when
blocks
are
to
be
located
by
identification,
an
eighth
byte
indicating
block
identification
must
be
included
in
this
field.
(The
actual
address
of
a
block
is
in
the
form
MBBCCHHR,
where
M
indicates
which
extent
entry
in
the
data
extent
block
is
associated
with
the
direct-access
program;
BB
indicates
the
bin
number
of
direct-access
volurre;
CC
indicates
the
cylinder
address;
HH
indicates
the
actual
track
address;
and
R
indicates
the
block
identification.)
EOV
End
of
Volume
The
EOV
mac:ro-instruction
identifies
end-of-volume
and
end-of-data
set
conditions.
For
an
end-of-volume
condition,
EOV
causes
switching
of
volumes
and
verification
or
creation
of
standard
labels.
For
an
end-of-data
set
condition,
EOV
causes
your
end-of-data
set
routine
to
be
entered.
When
using
XDAP,
you
issue
EOV
if
switching
of
direct-access
volumes
is
necessary,
or
if
secondary
allocation
is
to
be
performed
for
a
direct-access
data
set
opened
for
output.
The
only
parameter
of
the
EOV
macro-instruction
is
the
address
of
the
data
control
block
of
the
data
set.
CLOSE
--
Restore
Data
Control
Block
The
CLOSE
macro-instruction
restores
one
or
more
data
control
blocks
so
that
processing
of
their
associated
data
sets
can
be
terminated.
You
must
issue
CLOSE
for
all
data
sets
that
were
used
by
the
direct
access
channel
program.
Some
of
the
procedures
performed
when
CLOSE
is
executed
are:
Execute
Direct
Access
Program
(XDAP)
Macro-Instruction
101

Table of Contents

Other manuals for IBM System/360

Preview: User Guide
User Guide118 pages
Preview: Operating Guide
Operating Guide48 pages
Preview: Field Engineering Manual
Field Engineering Manual131 pages

Questions and Answers:

Question and Answer IconNeed help?

Do you have a question about the IBM System/360 and is the answer not in the manual?

IBM System/360 Specifications

General IconGeneral
BrandIBM
ModelSystem/360
CategoryDesktop
LanguageEnglish

Related product manuals