$ZA contains a status determined by the last read on the device. The value is a decimal integer with a meaning determined by the device as follows:

For Terminal I/O:

0Indicating normal termination of a read operation

1: Indicating a parity error

2: Indicating that the terminator sequence was too long

3: Indicating a hardware contention or failure

4: Indicating a system configuration issue

5: Indicating a process limit/quota being exceeded

9: Indicating a default for all other errors

For Sequential Disk and Tape Files I/O:

0: Indicating normal termination of a read operation

9: Indicating a failure of a read operation

For Foreign Magnetic tape I/O:

0: Indicating normal termination of an operation

1: Indicating that End-Of-Tape (EOT) was encountered

9: Indicating a default for all other errors

For Mailbox I/O:

Decimal representing $JOB (identifier) of the process that wrote the last message the current process read

$ZA refers to the status of the current device. Therefore, exercise care in sequencing USE commands and references to $ZA.

GT.M does not permit the SET command to modify $ZA.

For more information on $ZA, refer "Input/Output Processing".