X25AM Programming Manual

Errors and Error Recovery for ITI and PTP
X25AM Programming Manual—527201-001
5-4
Suggested Recovery Action
Suggested Recovery Action
Rather than testing for each error code, for example, in a CASE statement, the
following approach is recommended.
•
An OPEN is issued and completes with an error.
°
Delay 1 second.
°
Retry the OPEN for as long as seems reasonable for the application.
°
Issue a console message and abort the process after the retry limit is reached.
•
A CLOSE is issued and completes with an error.
°
Retry 3 times.
°
Ignore any additional errors.
•
For the errors listed in Table 5-2, recovery is application-dependent.
•
For all other errors (listed in Table 5-3 on page 5-5) the following is suggested:
°
Delay 1 second.
°
Retry the operation for as long as seems reasonable for the application.
°
After the retry limit is reached, print a console message.
°
If the problem is with a subdevice file, close and open it.
°
If the problem is not with a subdevice file, abort the application.
Table 5-2. Errors Requiring Application-Dependent Recovery (page 1 of 2)
Error
Returned
by ITI
Returned
by PTP Description
1 X A read procedure reached end-of-file or a write
procedure reached end-of-tape.
110 X The device is not ready or the controller is not
operational.
111 X Only BREAK access is permitted.
120 X A data parity error occurred, or an attempt was made to
access a tape whose density is higher than the switch
setting on the tape drive.
122 X X A request aborted due to possible data loss caused by
reset of the circuit, CLB sequence error; or a DP2 disk
process takeover occurred.
140 X X Modem error (communication link not yet established,
modem failure, momentary loss of carrier, or disconnect)
or FOX link to an EXPAND line handler is down.