Chapter 7 Board-control Commands
Page 7 - 46 |
| Extended Unit Options (18H) |
Extended Unit
Options Data
Structure
Description of Fields
The Data Structure that you will use to pass the Extended Unit Option parameters to the RF3880 adapter is similar to the format of the Unit Options Parameter Block.
The Data Structure must contain these fields:
Each of the fields of the Data Structure are described below:
Address |
| Byte Memory Address |
|
| ||
Offset | Offset + 0 | Offset + 1 |
| Offset + 2 | Offset + 3 |
|
|
|
| ||||
|
|
|
|
|
|
|
00H | Disconnect |
| Unit SCSI ID | 0 |
| |
|
|
|
|
|
| |
04H | Select |
| Retry Control | Retry Limit |
| |
|
|
|
|
|
|
|
08H | Reserved | Reserved |
| Sense Count | Unit Flags |
|
|
|
|
|
|
|
|
0CH | Sense Byte # | Sense Byte # |
| Sense Byte # | Sense Byte # | Status |
10H | Sense Byte # | Sense Byte # |
| Sense Byte # | Sense Byte # | Block #1 |
|
| |||||
|
|
|
|
|
|
|
14H | Sense Byte # | Sense Byte # |
| Sense Byte # | Sense Byte # | Status |
18H | Sense Byte # | Sense Byte # |
| Sense Byte # | Sense Byte # | Block #2 |
|
|
|
|
|
|
|
1CH |
|
| 0 |
|
| |
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.
Table 104: Extended Unit Options Data Structure
Unit SCSI ID
This field must contain a number from 0 - 15 representing a SCSI Unit on the bus. Do not use the RF3880 adapter SCSI ID you assign with the General Options command. (If you do you will receive the 02H (Bad Unit) error code.)
Disconnect
If you have enabled SCSI bus Disconnect with the General Options command, 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
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
0 ⇒ No
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 with 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).
21020285 D | User’s Guide |
