Ciprico Rimfire 3880 User Manual download pdf (Page 66)

21020285 D User’s Guide

Chapter 4 Command Operation

Page 4 - 8 The Base Status Block

Multiple

Status Blocks

It is possible to receive more than one Status Block to indicate the outcome of

a command. To receive multiple Status Blocks, when operating in Initiator

Mode, all the following must be true:

• You have used the Unit Options or Extended Unit Options Board-control

commands to set up retries and / or extended Sense data for Pass-through

commands.

• The command is a Pass-through command. (Board-control commands

are not subject to retries and do not return Sense Data.)

• The Pass-through command is issued through use of the Command List

structure. (Single command structures can only contain one Status

Block.)

It is also possible to receive multiple Status Blocks when operating in Target

Mode. You will receive two Status Blocks in Target Mode if the SCSI

Command Descriptor Block is more than six bytes. See Chapter 6 for more

information.

Setting up Unit Options

These are the options selected through the Unit Options and Extended Unit

Options Board-control commands that cause the Rf3880 to return multiple

Status Blocks in response to an error condition:

Retries - If you 1.) supply a Retry Limit value, 2.) select a type of retry in the

Retry Control field, and also 3.) set the ISB bit of the same field, each command

retry performed will generate at least one Status Block.

Sense Data - If you select a Sense Count greater than eight, or specify more

than eight Selected Sense Bytes, you will receive multiple Status Blocks for

each Request Sense command sent in response to Check Condition.

Note

If you enabled both Retries and nine or more byte of Sense Data, you will

receive multiple Status Blocks for every retry performed until either the

command completes successfully or the Retry Limit is reached. This can be

calculated as follows:

For a command that exhausts Retry Limits:

# of Status Blocks = (# of retries + 1)x(# of Status Blocks needed for

Sense Data)

For a command that recovers before Retry Limit is reached:

# of Status Blocks = ((# of attempts + 1)x # of Status Blocks needed for

Sense Data) + 1

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Ciprico Rimfire 3880 User Manual Page 66