A-46
HP
9895A
Disc
Memory
Command Set
Initialize
Type:
Purpose:
Description:
HP-IB Sequence:
ATN
(01ADDRS
1
Primary
Listen
ATN
P1101000
1 Secondary I
Disc write.
The Initialize
command
is used
to
set
or
re-set D bits. It is
similar to the buffered write with the following exception:
1.
For
HP
format discs, all D bits
on
the target track
will
be
set
or
re-set before the target sector
is
written.
2. For
IBM
format discs, the D bits of the target sector
are set
or
re-set
as
the sector
is
written.
The Initialize
command
is especially useful when used with
the Format command to make invisible tracks.
Following reception of
the
Initialize command, parallel poll
is
disabled
and
the status of the selected unit
is
checked.
If
an
HP
format disc
Is
present, the entire target track is
re-formatted, with the D bit in all sectors set
or
re-set ac-
cording to
the
D bit specified in the opcode byte of
the
command. This re-formatting has several results:
1.
All
data
on
the target track is lost,
2. The sector interleave of the track
is
changed
to
2
(every
other
sector),
3. The spiral offset of
the
target track may
no
longer
be
optimal.
If
an
IBM
format disc
is
present, the D bit
is
set
or
re-set
according to the D bit specified in the opcode data byte as
each sector
is
written. The initialization of
an
IBM
sector
does not affect the format
or
data of the remaining sectors
of
the
target track, as does
an
HP format.
After the initialize request
is
sent, the command accepts
and
writes data in a
manner
identical to the Buffered Write
command.
Initialize Request
EOI
ATN
P
P
P
D01011
1
UUUU
1
P
I P0111111 I
E E
Opcode
Unit
Unlisten
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