Radio Shack TRS-80 model III Owner's Manual page 85

TgSDOS
in
order to satisfy the request,
it
will
do
so.
"Spanning"
will
be handled by
trsdos
as necessary.
At
$init
$open
time the
dcb
value of
nrn
is
set to x'oooo*
so that
the
first
record
will
be
written.
After
each
logical record
is
transferred,
the
nrn
value
in the
dcb
will
be incremented
by
1
If
lrl
=
o,
$write
transfers
one
physical record
from buffer
into
the disk
file
using the
nrn
in
the
dcb. buffer
is
defined
at
$init/open time only.
The dcb
value
nrn
is
updated
as
above,
after
the
write.
Entry Conditions
(HL)
=
urec
if
lrl
is
not zero.
Unused
if
lrl
=
o
de
=
dcb
call $write
Exit
Conditions
Z
=
OK
a
=
trsdos
error
code.
$VERF—
17468/X'443C'
The only
difference
between $verf and $write
is
that
$verf
writes
one
physical
record
to
disk
and then reads
it
back
into
a special
trsdos
ram
area not defined
by
the user.
This
special area
and
the original write buffer are then
compared
byte
by
byte
to
assure
that
the
record
was
successfully written.
Entry
Conditions
(HL)
=
Same
as
$write
above.
(DE)
=
DCB
CALL $VERF
Exit
Conditions
Z
=
OK
a
=
trsdos
error code.
$PUTEXT—
17483/X'444B'
This
routine will
add an
extension
to
a
filename
if
an extension does not already
exist.
An
extension
to
a filename
may
be
useful for identifying the type of data
in the
file.
81