Specifications

5102ch04.fm Draft Document for Review May 12, 2014 12:46 pm
120 IBM Power System S822 Technical Overview and Introduction
isolation registers and from the associated logic. In firmware, this data consists of return
codes, function calls, and so forth.
FFDC
check stations are carefully positioned within server logic and data paths to ensure that
potential errors can be quickly identified and accurately tracked to a FRU.
This proactive diagnostic strategy is a significant improvement over the classic, less accurate
reboot and diagnose service approaches.
Fault isolation
The service processor interprets error data that is captured by the FFDC checkers (saved in
the FIRs or other firmware-related data capture methods) to determine the root cause of the
error event.
Root cause analysis might indicate that the event is recoverable, meaning that a service
action point or need for repair has not been reached. Alternatively, it might indicate that a
service action point was reached, where the event exceeded a predetermined threshold or
was unrecoverable. Based on the isolation analysis, recoverable error-threshold counts can
be incremented. No specific service action is necessary when the event is recoverable.
When the event requires a service action, additional required information is collected to
service the fault. For unrecoverable errors or for recoverable events that meet or exceed their
service threshold (meaning that a service action point was reached) a request for service is
initiated through an error logging component.
4.3.2 Diagnosing
General diagnostic objectives are to detect and identify problems so that they can be resolved
quickly. IBM diagnostics strategy includes the following elements:
򐂰 Provide a common error code format equivalent to a system reference code, system
reference number, checkpoint, or firmware error code.
򐂰 Provide fault detection and problem isolation procedures. Support remote connection
ability to be used by the IBM Remote Support Center or IBM Designated Service.
򐂰 Provide interactive intelligence within the diagnostics with detailed online failure
information while connected to IBM back-end system.
Using the extensive network of advanced and complementary error detection logic that is built
directly into hardware, firmware, and operating systems, the IBM Power Systems servers can
perform considerable self-diagnosis.
Because of the FFDC technology that is designed into IBM servers, re-creating diagnostics
for failures or requiring user intervention is not necessary. Solid and intermittent errors are
designed to be correctly detected and isolated at the time that the failure occurs. Runtime and
boot time diagnostics fall into this category.
Boot time
When an IBM Power Systems server powers up, the service processor initializes the system
hardware. Boot-time diagnostic testing uses a multitier approach for system validation,
starting with managed low-level diagnostics that are supplemented with system firmware
initialization and configuration of I/O hardware, followed by OS-initiated software test routines.
Boot-time diagnostic routines include the following items:
򐂰 Built-in self-tests (BISTs) for both logic components and arrays ensure the internal
integrity of components. Because the service processor assists in performing these tests,