In a message dated 7/24/2007 11:16:19 A.M. Central Daylight Time, [EMAIL PROTECTED] writes: >---------------------<snip>---------------- Does anyone know for sure which was the last DASD subsystem that cared about Rotational Positional Sensing (RPS) values? -------------------<unsnip>--------------- IIRC, that would be the 3390 (real, not emulated). To my knowledge, none of the RAID configurations care much about RPS data. The 3390 is not a subsystem. It is a device type. The subsystem in question would have to be one that is capable of driving a 3390, which include 3990, 9340, 9390, and 2105. IBM does not market RAID configurations to mainframe customers. It markets DASD subsystems that work according to the documentation in their control unit reference manuals, which say, or at least strongly imply, that sector values are still used. The real disks involved are RAID, but that's irrelevant. RAID configurations also do not care about the cylinder or track numbers that are known to the software running in the mainframe, but that doesn't mean the software can ignore these numbers. The DASD sub system reads an entire track into cache storage and then accesses that data as if it were on a real, SLED device type and according to the CCWs coming from the mainframe's central storage. When the subsystem needs to access the real disk(s), it maps the mainframe's CCHH and other control information into the appropriate commands and control information for whatever real RAID disks are inside the subsystem. RAID disks are FBA, so RAID configurations don't care about software's block sizes either. So no, the RAID does not care about sector numbers, but yes, the IBM DASD subsystems do. Bill Fairchild Plainfield, IL
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