Specifications

Chapter 4. Continuous availability and manageability 121
Draft Document for Review May 12, 2014 12:46 pm 5102ch04.fm
the system is enabled to perform fault determination and isolation, whether or not the
system processors are operational. Boot-time BISTs can also find faults undetectable by
processor-based power-on self-test (POST) or diagnostics.
򐂰 Wire-tests discover and precisely identify connection faults between components such as
processors, memory
򐂰 Initialization of components such as ECC memory, typically by writing patterns of data and
allowing the server to store valid ECC data for each location, can help isolate errors.
To minimize boot time, the system determines which of the diagnostics are required to be
started to ensure correct operation, based on the way that the system was powered off, or on
the boot-time selection menu.
Host Boot IPL
In POWER8 the initialization process during IPL has been changed a little bit. The Flexible
Service Processor (FSP) is no longer the only instance that initializes and runs the bootup
process. With POWER8 the FSP initializes the boot processes, but on the POWER8
Processors itself one part of the Firmware is running and performing the CEC chip
initialization. A new component called the PNOR Chip stores the Host Boot firmware and the
Self Boot Engine (SBE) is an internal part of the POWER8 Chip itself and is used to boot the
chip.
With this Host Boot initialization new Progress codes are available. An example for a FSP
Progress code is C1009003. During the Host Boot IPL Progress codes like CC009344
appear.
In case of a failure during the Host Boot process a new Host Boot System Dump is collected
and stored. This type of dump includes Host Boot memory and will be offloaded to HMC when
available.
Run time
All Power Systems servers can monitor critical system components during run time, and they
can take corrective actions when recoverable faults occur. IBM hardware error-check
architecture provides the ability to report non-critical errors in an
out-of-band communications
path to the service processor without affecting system performance.
A significant part of IBM runtime diagnostic capabilities originate with the service processor.
Extensive diagnostic and fault analysis routines were developed and improved over many
generations of POWER processor-based servers, and enable quick and accurate predefined
responses to both actual and potential system problems.
The service processor correlates and processes runtime error information by using logic
derived from IBM engineering expertise to count recoverable errors (called thresholding) and
predict when corrective actions must be automatically initiated by the system. These actions
can include the following items:
򐂰 Requests for a part to be replaced
򐂰 Dynamic invocation of built-in redundancy for automatic replacement of a failing part
򐂰 Dynamic deallocation of failing components so that system availability is maintained
Device drivers
In certain cases, diagnostics are best performed by operating system-specific drivers, most
notably I/O devices that are owned directly by a logical partition. In these cases, the operating
system device driver often works in conjunction with I/O device microcode to isolate and
recover from problems. Potential problems are reported to an operating system device driver,