Write buffer (3bh), Write data mode, Write – Dell PowerVault TL2000 User Manual

Page 98: Buffer, 3bh), Data, Mode

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WRITE

BUFFER

(3Bh)

Write

Buffer

is

used

with

Read

Buffer

as

a

diagnostic

function

for

testing

the

device

data

buffer,

DMA

engine,

SCSI

bus

interface

hardware,

and

SCSI

bus

integrity.

Additional

modes

are

provided

for

downloading

and

saving

micro

code

and

updating

Vendor

Unique

settings.

Bit

7

6

5

4

3

2

1

0

Byte

0

Operation

Code

(3Bh)

1

LUN

Reserved

Mode

2

Buffer

ID

3

(MSB)

4

Buffer

offset

5

(LSB)

6

(MSB)

7

Parameter

list

length

8

(LSB)

9

Control

Field

descriptions:

Mode:

The

Mode

field

is

used

to

select

the

mode

of

operation.

The

media

changer

supports

the

following

values

within

this

field.

0010b

Data

0100b

Download

microcode

0101b

Download

microcode

and

save

1010b

Echo

buffer

If

any

non

supported

value

is

set,

the

media

changer

terminates

the

command

with

a

Check

Condition

status.

The

sense

key

will

be

set

to

ILLEGAL

REQUEST

and

the

sense

data

to

INVALID

FIELD

IN

CDB.

Buffer

ID:

When

the

Mode

is

set

to

Download

micro

code

or

Download

micro

code

and

save,

the

Buffer

ID

should

be

set

to

zero.

When

the

mode

is

set

to

Vendor

Unique

operation,

the

Buffer

ID

indicates

the

requested

page

to

update.

If

the

value

of

the

Buffer

ID

is

not

supported

by

the

specified

Mode

the

command

is

rejected.

The

target

detects

and

rejects

commands

that

would

overrun

the

buffer.

Buffer

Offset:

The

Buffer

Offset

is

required

for

the

Download

micro

code

(and

save)

modes

and

optional

for

the

Vendor

Unique

and

Data

modes.

In

all

other

modes

the

Buffer

Offset

must

be

set

to

zero.

Write

Data

Mode

With

this

mode,

SCSI

bus

integrity

can

be

tested

in

conjunction

with

the

READ

BUFFER

command.

The

host

can

by

means

of

this

mode

send

up

to

256

bytes

to

the

media

changer.

This

data

can

be

retrieved

by

means

of

the

READ

BUFFER

command.

The

Buffer

Offset

specifies

the

offset

within

the

buffer.

Potential

buffer

overruns

are

detected

and

will

result

into

a

Check

Condition

the

sense

key

will

be

set

to

ILLEGAL

REQUEST

and

the

additional

sense

data

to

INVALID

FIELD

IN

CDB.

3-84

TL2000

and

TL4000

SCSI

Reference