Format Unit
Format
Unit
The
FORMAT UNIT command formats
the
Target media
into
Initiator-addressable logical
blocks according
to
Initiator
defined options. During execution
of
the
FORMAT
UNIT
command,
the
Target may perform a media defect management algorithm (which can be
controlled by
the
Initiator
using optional forms
of
the
command). Defect management
instructions (if any) are contained in
the
Defect List supplied
to
the
Target
in
the
Data
Out
phase of
the
command.
The
FORMAT
UNIT command ensures
that
the
media is
formatted
so
that
all
data
blocks
can be accessed. Any
data
residing on
the
media before this command is issued will
be
lost. Any log information will be cleared by
the
format operation.
The
current Mode Select
operating
parameters
will become
the
saved values
if
the
DSP
bit
in
the
defect
list
header is
zero
(0).
There are four possible sources of defect location information during execution
of
the
FORMAT UNIT command:
Plist
(Primary
Defect List).
The
list
of
permanent
defects supplied by
the
original
manufacturer.
The
Plist is stored outside of
the
Initiator-accessible logical block space.
The
Plist is accessible by
the
Target
(to
reference while formatting),
but
is
not
normally accessible
by
the
Initiator
except through
the
READ
DEFECT
command. Once created,
the
original
Plist
is
not
subject
to
change.
The
Format Unit command does
not
affect
the
Plist.
Clist (Target Certification List). This list includes defects detected
by
the
Target during an
optional certification process executed during
the
FORMAT UNIT command.
This
list will
be
added
to
the
Glist.
Dlist
(Data
Defect List). Supplied by
the
Initiator
in
the
Data
Out
phase
of
the
FORMAT
UNIT command.
Glist (Grown Defect List.) Maintained by the Target and includes all defects sent
to
the
Target from
the
Initiator
(the
Dlist), any defects identified by
the
Target during previous
and
current
FORMAT
UNIT
operations,
and
any defects identified by a REASSIGN BLOCKS
command.
The
Glist does
NOT
include
the
Plist.
Format Unit Command Descriptor Block (COB)
Bit
Byte
7
I
6
I
5
I
4
I
3
1
2
1
1
I
00
Opcode - 04H
01
Logical Unit
Number
I
FMTDTA
I
CMPLST
I
Defect List
Format
02
Vendor Unique
03-04
(MSB=03)
Interleave
(LSB=04)
05
Control
Byte
FMTDTA
(Format
Data).
Indicates whether
the
Initiator will send additional defect
information (Dlist)
to
the
Target.
If
set
to
zero (0),
there
will be no
Data
Out
phase,
the
Target will
not
receive a new Dlist,
all previous defect information (Glist)
is
retained,
and
the
CMPLST
bit
and
the
Defect List
Format
field will have no effect.
0
DRAFT
SCSI Command Descriptions A-7
1/18/93 09:58
To Next Page
Loading...
Need help?
General
