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AIX Version 4.3 Kernel and Subsystems Technical Reference, Volume 2

Reliability, Availability, and Serviceability (RAS) Daemon for the Serial DASD Subsystem

The RAS (Reliability, Availability, and Serviceability) daemon for the serial Direct Access Storage Device (DASD) subsystem provides off-level error handling support to the device driver. The main function of the daemon is to recognize signals from the device driver and take the appropriate action. One such action is to verify the downloadable microcode levels within the subsystem and to download appropriate levels again if necessary. This way, even errors within the subsystem causing the loss of downloaded microcode can be recovered.

The RAS daemon appears in the process table as sdd (serial DASD daemon). There is one daemon running for each serial DASD adapter in the system. This process should not be killed because it is there for enhanced data integrity and error recovery capabilities. The daemon cannot be respawned without unconfiguring and reconfiguring the affected adapter.

Related Information

Serial DASD Subsystem Device Driver.

Device-Dependent Subroutines for the Serial DASD Subsystem.

Error Conditions for Serial DASD Subroutines.

The /dev/rhdisk special file, /dev/serdasda special file, /dev/serdasdc special file.

The close subroutine, ioctl subroutine, the lseek subroutine, open or openx subroutine, read, readx subroutine, write, writex subroutine.

SD Error Identifiers for the Error Log in AIX Problem Solving Guide and Reference.

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