Basic
I/O
System (BIOS) Functions
If
an
error
occurs, the CBIOS attempts
16
retries to see
if
the
error
is
recoverable.
When an error
is
reported, the BDOS prints the message "BDOS
ERR
ON
x:
BAD
SECTOR", where x
is
the drive specifier. The
operator
then has the option
of
pressing RETURN to ignore the error,
or
CONTROL-C
to
abort.
Refer
to
Appendix I for information
about
blocking
and
deblocking.
WRITE
SELECTED
SECTOR
ENTRY
FUNCTION
14
WRITE
RETURN
AL: Return Code
OH,OFFH
This function writes the
data
from the currently selected
DMA
base
and
offset
address
to
the currently selected drive, cylinder (hard disk only), track,
and
sector.
This routine actually writes the
data
to a buffer
at
a fixed location
and
calls
R_
W _COMMON
or
R_
W
_COMMONHD
to perform the physical write.
The
error
codes given for Read Selected Sector (function
13)
are also returned in
register AL for this function, with error recovery attempts as described for
that
function.
Refer to Appendix I for information
about
blocking
and
deblocking.
RETURN
LIST STATUS
ENTRY
FUNCTION
15
LISTST
RETURN
AL: Return Code
OH,OFFH
This function returns the ready status
of
the list device. The value returned in
AL
is
00 if the list device
is
not ready
to
accept a character,
and
OFFH
if
a character
is
sent
to
the printer.
5-15
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