Information in Error and Operational Records

There are two types of records on the system’s ERDS:

RECORD TYPE	DESCRIPTION
Hardware and software errors	Reflect the failure and recovery of processors, channels, I/O devices, and operating system software.
Software operational data	Indicate the time and circumstances of the failures and other conditions.

Although the records reflect different events and are of different lengths, they all contain the following kinds of information:

Relevant system information at the time the record is generated
Device hardware status at the time the record is generated
Results of any device or control unit recovery attempt
Results of any software system recovery attempt
Statistical data about device usage and recoverable errors

Each record begins with a standard 24-byte header that contains the information to identify the type and origin of the records.

INFORMATION	DESCRIPTION
Type information	Includes the specific type of the record, the specific source of the record, the general reason the record is created, and special record-dependent data.
Origin information	Includes the operating system under which the record is generated, the date and time the record is generated, and the identity of the processor (CPU) on which the record is generated.

Note: For CCH, MCH and OBR records, the processor generating the record is also the processor associated with the error. In a tightly-coupled multiprocessing environment, this is not necessarily true for other types of records.

Hardware I/O errors are divided into the following groups in several of the EREP reports:

TYPE OF ERROR	DESCRIPTION	IN THE OBR
Temporary error	A read or write operation that failed, was retried, and eventually succeeded	Byte 3(Bit 1)=1 AND Byte 3(Bit 3)=0
Permanent error	A read or write operation that failed and was retried several times without success	Byte 3(Bit 1)=0 AND Byte 3(Bit 3)=0
Path error	A permanent error was found on one path and an alternate path was tried	Byte 3(Bit 3)=1
Note: Byte 3(Bit 1) is the temporary error bit and Byte 3(Bit 3) indicates whether or not another channel path has been tried.