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INPUT/OUTPUT PROVISIONS
26.2 -- Device Independent
lID
W (Bit 3) --
Rewindable device
flag
This bit indicates whether the
.REWND
function
is
valid
ror
the
device.
In the current version of
MDOS,
it
may
appear
as
i '
the
"W" flag
and
the
"L"
flag
are redundant,
because only the diskette device
can be used
rOT
logical
sector
I/O
and
only
the
diskette
device
can be "rewound"; however,
in order
to
a 11 ow
T
or
e x pan s ion,
the
. REWND
Fun c t
i
on's
processing
depends on the "W" flag.
If
the
"W" flag
is set to onel
the device can be reUlound.
If the trW"
flag is set to zero, the device cannot
be
rewound.
S (Bit 2) -- System console rlag
This
flag distinguishes the system console
~rom
all
other
devices.
This is needed since
the
record
input
runction
does
speCial
processing
ror
the
certain
control
characters
which
are
treated
differently
when
being.
input
from another device.
These
special characters
are
described
in
section
25.3.4.
If the liS" bit is set to one,
the device is
the
s~stemconsole.
If the US" bit is set
to
zero,
the aevice is not the
s~stem
console.
L (Bit 1) -- Logical sector lID flag
This
flag
is
used to tistinguish the diskette
drives
from
all
other
devices.
Since
the
two
specialized
lID
calls,
.GETLS and. PUTLS, are only
valid ror the diskette drives, a
-Flag
is
necessary
that
identifies that device.
If the "L" flag is set
to one,
logical sector
1/0
is
valid
(1.
e.
I
the device
is
the
diskette
drive).
If the "L" rlag is set to
ze,..o,
logical sector I/O is invalid
(1.
e.
I
the device
is not the diskette drive).
'\
./J
Page
26-06
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