Seagate Cheetah 15K.4 SAS, Product Manual

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Cheetah 15K.4 SAS Product Manual, Rev. B 7
3.0 General description
Cheetah drives combine giant magnetoresistive (GMR) heads, partial response/maximum likelihood (PRML)
read channel electronics, embedded servo technology, and a Serial Attached SCSI (SAS) interface to provide
high performance, high capacity data storage for a variety of systems including engineering workstations, net-
work servers, mainframes, and supercomputers. The Serial Attached SCSI interface is designed to meet next-
generation computing demands for performance, scalability, flexibility and high-density storage requirements.
Cheetah drives are random access storage devices designed to support the Serial Attached SCSI Protocol as
described in the ANSI specifications, this document, and the SAS Interface Manual (part number 100293071)
which describes the general interface characteristics of this drive. Cheetah drives are classified as intelligent
peripherals and provide level 2 conformance (highest level) with the ANSI SCSI-1 standard. The SAS connec-
tors, cables and electrical interface are compatible with Serial ATA (SATA), giving future users the choice of
populating their systems with either SAS or SATA hard disc drives. This allows you to continue to leverage your
existing investment in SCSI while gaining a 3Gb/s serial data transfer rate.
The head and disc assembly (HDA) is sealed at the factory. Air recirculates within the HDA through a non-
replaceable filter to maintain a contamination-free HDA environment.
Note. Never disassemble the HDA and do not attempt to service items in the sealed enclosure (heads,
media, actuator, etc.) as this requires special facilities. The drive does not contain user-replaceable
parts. Opening the HDA for any reason voids your warranty.
Cheetah drives use a dedicated landing zone at the innermost radius of the media to eliminate the possibility of
destroying or degrading data by landing in the data zone. The heads automatically go to the landing zone when
power is removed from the drive.
An automatic shipping lock prevents potential damage to the heads and discs that results from movement dur-
ing shipping and handling. The shipping lock disengages and the head load process begins when power is
applied to the drive.
Cheetah drives decode track 0 location data from the servo data embedded on each surface to eliminate
mechanical transducer adjustments and related reliability concerns.
The drives also use a high-performance actuator assembly with a low-inertia, balanced, patented, straight arm
design that provides excellent performance with minimal power dissipation.