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Hitachi Deskstar 7K400 and 7K250 HDD


And here are the heroes of our review:




Hitachi Deskstar 7K400 and 7K250 hard disks: the HDS724040KLAT80 (above) and the HDS724040KLSA80 (in the center) with UltraATA and Serial ATA interfaces correspondingly and the HDS722525VLSA80 (below).

These models look a tad differently: there has again appeared a screw over the spindle axis on the top cover of the "five-platter" cans (perhaps it "reinforces" the construction, as it was in IBM hard disks in the DTLA era), and the 7K400 PCB has grown in size compared to similar (in interface) 7K250 models. The form of the massive plate on the back of the can has also been changed.

It's nice of Hitachi to use "double" power supply for SerialATA models — you can power the storage device either via the new standard SerialATA power connector (which is necessary, for example, when you want to use these disks in "storage-cages" and mobile racks) or via the traditional four-pin connector (which is guaranteed in any power supply unit, even in the old models).

Though in practice, when testing SATA devices of the 7K250 and 7K400 series I found out that when powered via a SATA power connector these devices were not very stable and sometimes they started to clunk their heads (sudden multiple cycles of parking-lifting off). This negative effect disappeared only after the disks were powered "after the old way" — via the 4-pin connector (we haven't noticed such effects in hard disks from other manufacturers). Let's write it off to the "presence effect" and hope that there will be no such thing when these drives operate with proper power supply units or power adapters.

Here you can read about the proprietary technologies used in Hitachi Deskstar 7K400:

Load / unload technology
AFC "pixie dust" media
Giant magnetoresistive (GMR) head technology
Fluid dynamic bearing spindle motors
Audio/Visual - Seamless Streaming
Hitachi Deskstar 7K400 Mechanical Enhancements
Hitachi Power & Acoustic Management
Using Rotational Vibration Safeguard (RVS) Control to Minimize Disturbance Effects in Hard Disk Drives

Besides, Rotation Vibration Safeguard technology improves hard disk performance in high vibration conditions. It's designed for three or more hard disks used simultaneously. Latched SATA connector is an improved latch for Serial ATA connectors, which prevents self-disconnects, for example, in high vibration conditions.

Hitachi emphasizes that Deskstar 7K400 hard disks are designed not only for traditional high-performance and gaming PCs and workstations, but also for NearLine Storage (disk-to disk backups, archive and constant content storage, data loss prevention and data restoration), as well as for digital video recorders, home media-servers, and video editing and storage devices. It's also stressed that these disks use the latest interface technology — ATA-7, which provides for the special set of commands to transmit data streams (including audio and video) and has an improved SMART diagnostics (including self-diagnostics). Among the useful ATA-7 features one can note reading storage device attributes and configuring the disk buffer for better performance, recording data streaming errors to reduce error correction delays and obtain complete data restoration after these errors.

Aside from these three "top" models of the 7K400 and 7K250 series, our review also features another two Hitachi models for comparison purposes (we shall compare them with hard disks from other manufacturers another time) — the HDS722516VLAT20 160 GB hard disk, which is also from the Deskstar 7K250 series, but with UltraATA/100 interface and 2 MB buffer (all the other models in this review have 8 MB buffers), and a senior hard disk of the previous generation (based on three 60 GB platters) — IBM/Hitachi Deskstar 180GXP, IC35L180AVV207-1 180 GB model with UltraATA/100 interface and 8 MB buffer.

Alex Karabuto (lx@ixbt.com)
January 18, 2005

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