Compaq ProLiant 1200 Manual page 5

ECG0094/1197
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A Pentium processor requires tightly controlled power from a dedicated power supply. If a power
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supply module supporting a processor fails, the system goes down. To prevent that, Compaq
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servers have three processor power supply modules to support every two processors (two active
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and one redundant) or, in some models, fully redundant power modules. If one power module fails,
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the redundant power module takes over operation without interrupting system operation.
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To minimize the impact of a software, memory, or processor failure, Compaq implements rapid
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recovery tools in the system management hardware, software, and firmware that are included on all
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Compaq servers. Two of these tools, Automatic Server Recovery-2 (ASR-2) and Server Health
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Logs, work together to restore a server to its original state. If an error occurs in a subsystem, ASR-2
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will log the error in the Server Health Logs, attempt to restart the system, and take other necessary
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action to avoid subsequent faults, as specified by the system administrator.
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For example, if a processor becomes inoperable or fails the power-up self-test, power to that
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processor is disconnected and the boot process continues. The other processors continue to run, and
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an alert message is sent to the system administrator. Replacement of the failed processor can be
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scheduled to minimize downtime.
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I/O Expansion
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A number of developments are improving the availability of expansion cards. With the
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implementation of redundancy and, in some areas, hot plug capability, Compaq servers continue to
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move closer to the goal of maximum system reliability.
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Compaq leads the industry in developing and delivering PCI Hot Plug technology. Compaq's PCI
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. . Hot Plug Adapter technology allows hot replacement, which is the replacement of one PCI adapter
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with an identical adapter while the system is operating. This technology also includes hot upgrade
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(replacement of a PCI adapter with an upgraded adapter) and hot expansion (addition of a PCI
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adapter to an empty slot).
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A standard implementation (compliant with PCI SIG guidelines), Compaq's PCI Hot Plug Adapter
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. . technology is backward compatible. A PCI Hot Plug Adapter can be installed without using its hot
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plug functionality until such time as all the requirements (PCI Hot Plug Adapter, a hot plug aware
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operating system, a user interface, and hot plug device driver support) are in place. This allows a mix
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of the existing components and the new hot plug technology to be in use at the same time, protecting
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. . the substantial investment companies make in network and storage hardware, and allowing a gradual
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move toward improved system availability in a cost-effective manner.
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Intel has licensed the Compaq PCI Hot Plug Controller for use on its system board products.
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All industry-standard PCI adapters can be used in Compaq's hot plug environment without
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modification. However, device drivers require new features to enable use of Compaq servers' hot
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plug capabilities. Leading independent hardware suppliers committed to modifying their device
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drivers to be hot plug aware include Adaptec, Dialogic, Digi International, Mylex, Standard
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Microsystems Corporation, and SysKonnect. In addition, Compaq is delivering hot plug capable
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drivers for its own leading PCI server adapters.
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Support for PCI Hot Plug technology is being built into current and upcoming versions of Windows
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NT 5.0, Novell IntranetWare, and SCO UNIX operating systems. For more information about PCI
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Hot Plug, see technology briefs 398A/1196, PCI Hot Plug Technology; ECG004.0897, PCI Hot
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Plug Technology with SCO Software Architecture;
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Microsoft Windows NT Environment, and 131A/0397, PCI Hot Plug Technology with Novell
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Architecture.
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Eliminating Single Points of Failure (cont.)
Deploying PCI Hot Plug in a
064A/0797,