Ciprico Rimfire 3880 manual Flags-2, Bit-meanings of Flag-2 Field, Meaning of TAG Opts Bits

Chapter 5 Initiator Mode Pass-through Commands
Initiator Pass-through Parameter Block Format					Page 5 - 9
	Opcode	DAT	DIR	Description
	E4H	1	0	Ciprico defined
	E5H
	thru	0	0	not defined
	EFH
	F0H	0	0	Ciprico defined
	F1H	0	0	not defined
	F2H	0	0	not defined
	F3H	0	0	not defined
	F4H	0	0	Ciprico defined
	F5H
	thru	0	0	not defined
	FFH

Table 30: DAT and DIR Automatic Settings

Flags-2

The bits of this field are used to select SCSI-2 and additional command control features implemented by the RF3880 adapter. The meanings of the bits are as follows:

BITS

7	6	5	4	3	2	1	0
0	0	0	0	JSM	IAD	TAG OPTS

Table 31: Bit-meanings of Flag-2 Field

Note

Depending on the SCSI- 2 device you are using, you may also need to enable tagged queuing with a MODE SELECT page 0AH, Common Device-Type Control Parameters command to the device. See your vendor-supplied peripheral documentation for more information.

TAG OPTS - These two bits let you choose the tagged queuing method you wish used with the current command. You can choose one of three types of messages for the RF3880 adapter to use when issuing the command.

TAG OPT	Meaning:
Value

SIMPLE QUEUE TAG MESSAGE: The command may be processed

00by the SCSI-2 device out of sequence for efficiency. Example: device may sort commands by logical block address.

ORDERED QUEUE TAG MESSAGE: The command must be

01executed by the SCSI-2 device in the order sent by the adapter (in order with respect to other commands sent with the ORDERED QUEUE TAG MESSAGE).

HEAD OF QUEUE TAG MESSAGE: The command is executed by

10the SCSI-2 device before all other commands previously sent, including other Head of Queue Tag commands but excluding command currently in process.

11 Reserved

Table 32: Meaning of TAG OPTS Bits

In order for these bits to apply to the current operation you must have already enabled tagged queuing with either the Unit Options or Extended Unit Options command. These commands are covered in detail in Chapter 7, Board-control Commands. If you do not enable tagged queuing with the Unit Options or Extended Unit Options command, the TAG OPTS bits are ignored.

For more information about the use of tagged queuing, see the usage discussion in Chapter 8.

User’s Guide 21020285 D