Ciprico Rimfire 3880 Board-control Commands Unit Options 08H Disconnect Time-out, Retry Limit

Chapter 7 Board-control Commands

Unit Options (08H) Page 7 - 19

Disconnect Time-out

Note

The sequentially recorded nature of tape media is such that positioning for retries requires extra commands. For this reason, do not enable the retry function for SCSI tape devices.

If you have enabled SCSI bus Disconnect/Reconnect with the General Options command (DIS bit of Select Flags is set), this field selects — for the specified unit — the amount of time the adapter will wait for a reconnect. If a reconnect does not occur within the time defined, the adapter will post a time-out error (1FH) in the appropriate command Status Block.

The time appropriate for a disconnect depends on the action and the unit performing the task (seeks, rewinds, etc.). For this reason, the Disconnect Time- out value is tailored per unit with a latitude of 100 milliseconds to almost two hours. You may also choose the option of no time-out for this unit. In that case, the device or SCSI bus must be reset to recover from the failure.

0 ⇒ No time-out occurs; SCSI bus or device must be reset to clear a failure. Each increment ⇒ 100 milliseconds.

Retry Limit

If retries are enabled in the Retry Control field, (discussed next) this field specifies the maximum number of retries to attempt before reporting an error. Once the retry limit is reached, the error condition reported on the last retry is returned in the Status Block.

You must provide a value in this field or retries will not occur even if enabled (in the Retry Control field).

Retry Control

This field is used to particularize the retry operation for this unit. This field allows you to select the type of errors to retry and how they are reported.

BITS

7	6	5	4	3	2	1	0
0	0	0	RBE	RCE	RPE	ISB	INT

Table 75: Retry Control

INT Issue Interrupt - When ISB bit is set, allows you to select whether the adapter posts an interrupt for retry Status Block(s) when returned. Valid only when ISB bit is set.

0 ⇒ Do not interrupt for retry Status Block(s).

1 ⇒ Interrupt when retry Status Block(s) returned.

ISB Issue Status Block - Allows you to select that a Status Block be returned for each command retry performed. Enabling this will cause multiple Status Blocks to be returned for a command that requires retries.

0 ⇒ Do not issue a Status Block for each retry.

1 ⇒ Issue a Status Block for each retry.

RPE Retry Parity Errors - Allows you to retry SCSI commands that failed with a parity error.

0 ⇒ Do not retry for parity errors.

1 ⇒ Retry parity errors.

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