This parameter is designed for driver developers, to assist users who are experiencing non-recoverable errors due to driver issues.
When this parameter is set, the data structure used for communication between a driver and the I/O server (referred to as the DCB) is monitored for changes. If an error occurs, a Kernel and syslog message is generated.
Default Value: 0
With [debug]drivercheck=1 set, the DCB is checksummed.
On return, the checksum is checked as well as a flag at the end of the DCB buffer; for example:
*** WARNING: DriverCheck=1 DCB->buffer overrun ***
*** WARNING: DriverCheck=1 DCB corrupted/changed ***
Receipt of this message may not represent a serious error. If a driver cleared the whole DCB buffer of 554 bytes, then expect this error.
If a driver modifies the point information, expect notification via a DCB corruption message.
[debug]drivercheck=2 will additionally verify that a DCB belongs to a given unit. If this is not the case, an error will be logged.