January 2009

Zoned Recording Increases the number of sectors on the outer tracks of the drive since the circumference of the outside tracks is greater. This type of recording affords more disk capacity because there can be more sectors on the larger outer tracks than would be possible if the number of sectors per track were constant for the whole drive.…

Year 2000 Problem, or Y2K The risk that computers will be disabled or perform incorrectly if they read the two-digit abbreviation “00” to mean the year 1900 instead of the year 2000, as intended. The problem is said to have originated when early computer programmers abbreviated year dates to save storage space that was scarce and costly at the time.…

WD Caviar® The trade name for Western Digital’s line of hard drives for desktop personal computers. WD Enterprise The trade name for Western Digital’s line of enterprise hard drives. Winchester Disk Former code name for an early IBM hard disk model, sometimes still used to refer to the technology and design of most traditional hard drives.…

Value-added Reseller (VAR) Often referred to as a “Var” or “Reseller.” The independent professionals who market computer systems and components and who add value by performing assembly, upgrades, training and other services. Viterbi Detection An algorithm used in read channel technology that detects an entire sequence of data bits at a time and determines the most likely sequence of data bits by comparing actual sequence of data bit samples with sequences of possible data bit sample to accurately detect that data written to disk.…

Ultra SCSI Provides 20 MB/s transfers over an 8-bit bus or 40 MB/s transfers over a 16-bit Wide SCSI bus. Also known as Fast-20 SCSI, this feature is most commonly found in SCSI-3 drives. Ultra DMA/33 A high-speed host data transfer feature that transfers data at 33.3 MB per second.…

Tagged Queuing The ability of the drive to receive multiple I/O processes from each initiator. Task File The set of I/O Host Interface Registers used to transfer status, commands, and data between the host and the drive for the EIDE interface.…

SCA-2 SCA-2 (Single Connector Attach) interface incorporates a grounding contact, blindmate connector, direct plug misalignment tolerance, ESD protection, hot swap capability, and backplane connector options for SCSI devices. SCA-2 is commonly called the 80-pin SCSI connector. Small Computer System Interface (SCSI) An interface between a computer and peripheral controllers.…

Radial Path The straight-line path from the center of the disk to the outer edge of the disk. Random Access Memory (RAM) Memory that allows any storage location to be accessed randomly, as opposed to tape drives, which are sequential access devices.…

Qualification The process by which sample components are tested for their compatibility and utility as parts of a system. Western Digital OEM customers qualify WD hard drives for use in their computers. Queue A first-in-first-out (FIFO) data structure used to sequence multiple demands for a resource such as a printer, processor, or communications channel.…