Advertisement
INPUT/OUTPUT FUNCTIONS
25.3 -- Device Independent liD Functions
F (Bit 2) -- Non-file format flag
I'
"F"
is
set to one} the non-file 'ormat mode
is indicated.
In
this mode, all 1/0
must
be
to
a
non-diskette device.
No FDR (File Descriptor Record)
processing is performed.
The only valid file
format
that
can be supported in this mode is ASCII (FMT
=
5
of
IOCFDFL
1ft
he'·
F
U
,
1 a g iss e t to z e
l' 0
I
the n t h e
f
i
1 e
format
mode
is indicated.
In this mode;
1/0
can be
either to a diskette
or
to a non-diskette device.
If
a
non-d is k ette
d evi c e is being used
I
FDR proc ess ing
IJJ
i 11 b
e p er f
01"
m e
d .
T hat i s
I
an FDR
t1I
i
11
be
Ulr
itt eon
to the device if opened ror outputl
or an FDR will be
saarchad fcr
file
format
the diskette.
on the device
if
opened
~or
input.
The
mode (F
=
0) must be used ror accessing
M (Bits 0-1) -- Mode rlag
The mode flag can take on one of four
different
values:
00
=)
Open an existing Pile (diskette only) ror
, either input or output.
01
=~
Open an existing diskette rile or open a
device for input only.
10
=/
Create a
new
diskette file or open a device
for output only.
11
=)
Open an existing rile or create a new rile
<diskette only) ror either input or output.
The update modes (M = 00 or 11) can only be used
when accessing diskette riles.
The way in which
the
rour
different
modes
are
used is described in the
. OPEN
function,
section 25.3.3.
25.3.
1.
3
IOCDBP --
Data bufrer pointer
This two-byte field
OT
the rOCB is
used
as
a
working
storage
area
by
the record
IIO
~vnctions,
This
~"try
should
not be changed by the calling program once lID functions have
been called.
25.3.
1.
4 IOCDBS -- Data
burreT"
start
-~\
__ . "..J
This
two-byte
field of the IoCB must be initialized
by
J I
the calling program
berore
any
record
IIO
runctions
are
Page
25-22
Advertisement
