Temporary Error Limits

EREP uses both the nnn (MBYTES/ERROR) and ct (total errors) values to establish thresholds for temporary errors. The errors are reported on the subsystem exception report if both of the following criteria are met:

The number of megabytes processed per error is less than the number of megabytes specified by the error frequency (nnn) value
The number of times the error occurs is greater than or equal to the number specified by the count (ct) value

If you want the subsystem exception report for a 3420 tape subsystem to report 1600 bpi volume temporary read errors when:

Less than 599MB are read per error
The errors occur at least 5 times

Set the volume read limit control card as follows:

LIMIT 3420,VR1600=599(5)

With this setting:

WHEN	AND	THEN
Temporary read errors occur at a rate of 500MB per error	6 errors occur	The errors are reported on the subsystem exception report.
Temporary read errors occur at a rate of 600MB per error	6 errors occur	The errors are not reported on the subsystem exception report.
Temporary read errors occur at a rate of 500MB per error	4 errors occur	The errors are not reported on the subsystem exception report.

Note:

To cover all the possible sources of errors for a 34XX device, code LIMIT control statements for both hardware and volume read and write errors. Results are unpredictable if any values are omitted, or if a value is coded as zero.
If you do not code LIMIT control statements for a tape device or volume, the subsystem exception report includes only the permanent errors recorded against that device or volume.
Important: All temporary errors appear in the temporary error summary.
To force EREP to show all the temporary errors on the subsystem exception report, use 999(1) for the nnn(ct) variables on the LIMIT statement, provided that the number of megabytes processed per error is less than 999.
The density of 6250 BPI applies only to 3420 and 3430 drives. A LIMIT control statement for 34XX is ignored for 3410 devices.
If a tape drive is operating at a density other than 1600 or 6250 BPI, EREP uses the LIMIT values you specify for 1600 BPI.
Only one LIMIT control statement is allowed for the general 34XX type.
You may not continue a LIMIT control statement from one line to the next.
You should use separate LIMIT control statements to establish hardware and volume limits for a device.
If the device operates at both 1600 and 6250 BPI, you must use separate statements.

If only one tape density is involved, you can combine all four keywords on the same LIMIT control statement. For example, you may want to see the temporary errors for your 3410 and 3420 drives, operating at 1600 BPI density, as follows:

Hardware / Volume	R/W	Errors
Hardware	Read	1 or more errors, at 25MB per error
Hardware	Write	15 or more errors, at 10MB per error
Volume	Read	1 or more errors, at 25MB per error
Volume	Write	15 or more errors, at 10MB per error
Note: To set these limits, you can code the following LIMIT control statements: `LIMIT 3410,HR1600=025(1),HW1600=010(15),VR1600=025(1),VW1600=010(15) LIMIT 3420,HR1600=025(1),HW1600=010(15),VR1600=025(1),VW1600=010(15)` Because the limiting values and density are the same, these two statements can be combined into a single 34XX LIMIT control statement: `LIMIT 34XX,HR1600=025(1),HW1600=010(15),VR1600=025(1),VW1600=010(15)`

When your 34XX devices are operating at different densities, you cannot fit all four sets of keywords on the single 34XX LIMIT control statement.
If you specify only the volume or hardware values for both densities on a single 34XX LIMIT control statement, EREP applies those values to whichever kinds of errors you have not specified. For example:
```
LIMIT 34XX,VR1600=010(1),VW1600=010(1),VR6250=020(1),VW6250=020(1)
```
EREP applies the values specified here for volume reads and writes to hardware reads and writes for all your 34XX devices.
Important: When EREP checks the LIMIT control statement syntax, it fills in any blanks it finds with the corresponding values supplied elsewhere on the same statement. This is why results can be unpredictable when you do not code all the values on a LIMIT control statement or code a value as zero.