The IBM zEnterprise A system introduced a new and innovative redundant array of independent memory (RAIM) subsystem design as a standard feature on all zEnterprise servers. It protects the server from single-channel errors such as sudden control, bus, buffer, and massive dynamic RAM (DRAM) failures, thus achieving the highest System z A memory availability. This system also introduced innovations such as DRAM and channel marking, as well as a novel dynamic cyclic redundancy code channel marking. This paper describes this RAIM subsystem and other reliability, availability, and serviceability features, including automatic channel error recovery; data and clock interface lane calibration, recovery, and repair; intermittent lane sparing; and specialty engines for maintenance, periodic calibration, power, and power-on controls.

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This Laboratory concurs in the findings of this report and recommends the use of this type of equipment on Army aircraft. Several manufacturers have recently i ntroduced chargers that are simi lar to the uni ts described herein. It is recommended that each unit be judged on its own meri ts. The technical monitor for this program was Mr. Joseph D. Di ckinson of the A pplied Aeronauti cs Technical Area , Aeronauti cal Systems Di vi si on. DISCLAIMERS The findings in this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. When Government drawings, specifications , or other data are used for any purpose other then in connection with a definitely related Government procurement operation, the United States Government thereby incurs no responsibility nor any obligation whatsoever; and the fact that the Government may have formulated, furnished. or in any way supplied the said drawings , specificat,ons, or other data is not to be regarded by implication or otherwise as in any manner licensing the holder or any other person or corporation , or conveying any rights or permission , to manufacture , use, or sell any patented invention that may 'n any way be related thereto. Trade names cited r this report do not constitute an official endoisement or approval of the use of such commercial hardware or software .