'--.--
CDU-541
CD-ROM
DRIVE
SCSI
INTERFACE
MANUAL
5.2.
18.
READ
EXTENDED
Command
==============================================================================
Bit:
7
6
5
4
3
2 1
o
Byte
:
==============================================================================
o :
Operation
Code (28h) I
-----1-----------------------------------------------------------------------1
1 :
Logical
Unit
Number
:
Reserved
:
-----:-----------------~-----------------------------------------------------:
2 :
(MSB)
:
-----1--- ---I
3 : I
-----1---
Logical
Block
Address ---I
4 I I
-----1---
---I
5 I (LSB) I
-----l-------------~---------------------------------------------------------:
6 I
Reserved
I
-----1-----------------------------------------------------------------------:
7 I
(MSB)
I
-----1---
Transfer
Length
---I
8 I
(LSB)
I
-----i-----------------------------------------------------------------------1
9 i
Control
Byte
I
==============================================================================
The
READ
EXTENDED
comma~d
~equests
that
the
controlle~
transfer
data
to
the
initiator.
The
data
will
be
transferred
in
whole
blocks
without
delays
occurring
during
a
block
transfer.
The
logical
block
address
specifies
the
logical
block
at
which
the
read
operation
will
begin.
The
transfer
length
specifies
the
number
of
contiguous
logical
blocks
of
data
that
will
be
transferred.
A
transfer
length
of
zero
indicates
that
no
logical
blocks
will
be
transferred
but
the
addressed
drive
will
perform
a
seek
operation
to
the
specified
address.
This
condition
will
not
be
considered
as
an
error.
Any
other
value
indicates
the
number
of
logical
blocks
that
will
be
transferred.
See
the
READ
command
for
exception
handling
description.
5-33