Error Correction And Parity Checking; Status Leds - Sun Microsystems Enterprise 250 Owner's Manual

system. Reliability refers to a system's ability to operate continuously without
failures and to maintain data integrity. System availability refers to the percentage of
time that a system remains accessible and usable. Serviceability relates to the time it
takes to restore a system to service following a system failure. Together, reliability,
availability, and serviceability provide for near continuous system operation.
To deliver high levels of reliability, availability and serviceability, the system offers
the following features:
4 Error correction and parity checking for improved data integrity
4 Easily accessible status indicators
4 Hot-pluggable disk drives
4 Support for RAID 0, 1, and 5 storage configurations
4 Environmental monitoring and fault protection
4 N+1 power supply redundancy
4 Hot-swappable power supplies
4 Automatic system recovery (ASR)
4 Hardware watchdog mechanism
4 Four different levels of system diagnostics
4 Remote System Control (RSC)

Error Correction and Parity Checking

Error correcting code (ECC) is used on all internal system data paths to ensure high
levels of data integrity. All data that moves between processors, I/O, and memory
have end-to-end ECC protection.
The system reports and logs correctable ECC errors. A correctable ECC error is any
single-bit error in a 64-bit field. Such errors are corrected as soon as they are
detected. The ECC implementation can also detect double-bit errors in the same
64-bit field and multiple-bit errors in the same nibble (4 bits).
In addition to providing ECC protection for data, the system offers parity protection
on all system address buses. Parity protection is also used on the PCI and SCSI
buses, and in the UltraSPARC CPU's internal and external cache.

Status LEDs

The system provides easily accessible light-emitting diode (LED) indicators on the
system front panel, internal disk bays, and power supplies to provide a visual
indication of system and component status. Status LEDs eliminate guesswork and
simplify problem diagnosis for enhanced serviceability.
Sun Enterprise 250 Server Owner's Guide ♦ Revision A, June 1998
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