External RAID controllers are external devices for higher-end design systems. In this case, the RAID controller is removed completely from the system to a separate box. Within the box the external RAID controller manages the drives in the array, typically using SCSI, and then presents the logical drives of the array over a standard interface (again, typically a variant of SCSI) to the server using the array. The server sees the array or arrays as just one or more very fast hard disks; the RAID is completely hidden from the machine. In essence, one of these units really is an entire computer unto itself, with a dedicated processor that manages the RAID array and acts as a conduit between the server and the array.
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Bus-based RAID controllers are computer boards that are installed in a personal computer (PC) or server and connected to the array drives. They take the place of the SCSI host adapter or IDE/ATA...
Western Digital’s Raptor WD1500 is the highest-performing desktop SATA hard drive currently available. With support for NCQ and RAID-specific, time-limited error recovery, Raptor WD1500 drives...
Overview In 1993, the first edition of The RAIDbook was published by the RAID Advisory Board. This book formed part one of the RAID Advisory Board's objectives the standardization of terminology for...
3.2 Redundant Array of Independent Disks In the 1980's, when disk drives began to come down in price and improve in reliability, a group of three University of California at Berkeley professors...
2.5 Hardware Tuning The world would be much simpler if tuning the hardware could be done independently from tuning the software. Unfortunately, the two are intimately related. Although expert tuners...
