BIOS
Disk
Definition Tables
7-2
Table 7-1 Disk Parameter Header Elements
ELEMENT
DESCRIPTION
XLT
Offset
of
the logical-to-physical translation vector,
ifused
for this
particular drive,
or
the value
OOOOH
if
no sector translation takes
place (i.e., the physical
and
logical sector numbers are the same).
Disk drives with identical sector skew factors share the same
translate tables.
0000
Scratchpad values
for
use within the BDOS (initial value
is
unimportant).
DIRBUF
Offset
of
a 128-byte scratchpad area for directory operations
within
BDOS. All
DPHs
address the same scratchpad area.
DPB
Offset
of
a disk
parameter
block
for
this drive. Drives with
identical disk characteristics address the same disk
parameter
block.
CSV
Offset
of
a scratchpad area used for software check for changed
disketts. This offset
is
different for each
DPH
and
is used for
floppy diskettes only.
ALV
Offset
of
a scratchpad
area
used by the BDOS to keep disk storage
allocation
information.
This offset
is
different
for
each
DPH.
Table 7-2 lists the
DPH
values for the APC.
DIRBUF
CSV
ALV
Table 7-2
DPH
Values For The
APe
FO-ID
FD-2D
128
bytes
128
bytes
16
bytes
64 bytes
x 4 drives
x 4 drives
31
bytes
62 bytes
x 4 drives
x 4 drives
HARD
DISK
128
bytes
a
71
bytes
x 4 drives
CPMSPT=
64
SECMSK
=
63
To Next Page
Loading...
