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Hard Disk Enclosure

Disk Enclosure


A disk enclosure is a computer storage device designed to contain disk drives. The term is normally used to differentiate such a device from a more advanced disk array which contains a controller and supports RAID. Therefore, a disk enclosure is a simple container, sometimes with a power supply, but very little intelligence. Many disk enclosures are small portable devices that use USB, FireWire, or a special external version of Serial ATA to connect to a computer. In enterprise storage, the term normally refers to a device which can hold a number of disk drives (normally 4 or more) and which communicates with a server using the SCSI or fibre channel protocols.

  • USB enclosure Category:Rotating disc computer storage media Category:Computer storage devices

    Hard Disk


    A hard disk (or "hard disc" or "hard drive" or "hard disk drive") is a computer storage device that stores data on rotating magnetic surfaces.

    Mechanics

    A hard disk uses rigid rotating platters (disks). It stores and retrieves digital data from a planar magnetic surface. Information is written to the disk by transmitting an electromagnetic flux through an antenna or ''write head'' that is very close to a magnetic material, which in turn changes its polarization due to the flux. The information can be read back in a reverse manner, as the magnetic fields cause electrical change in the coil or ''read head'' that passes over it. A typical hard disk drive design consists of a central axis or spindle upon which the platters spin at a constant speed. Moving along and between the platters on a common armature are the read-write heads, with one head for each platter face. The armature moves the heads radially across the platters as they spin, allowing each head access to the entirety of the platter. The associated electronics control the movement of the read-write armature and the rotation of the disk, and perform reads and writes on demand from the disk controller. Modern drive electronics are capable of scheduling reads and writes efficiently across the disk, and of remapping sectors of the disk which have failed. Also, most major hard drive and motherboard vendors now support S.M.A.R.T. technology, by which impending failures can often be predicted, allowing the user to be alerted in time to prevent data loss. The (mostly) sealed enclosure protects the drive internals from dust, condensation, and other sources of contamination. The hard disk's read-write heads fly on an air bearing (a cushion of air) only nanometres above the disk surface. The disk surface and the drive's internal environment must therefore be kept immaculately clean, as fingerprints, hair, dust, and even smoke particles have mountain-sized dimensions when compared

    Hard Disk


    IEC Binary Prefixes

    My feeling is that all the storage capacity units in this article should be changed to the IEC Binary Prefixes for clarity. The only objection I can see to this is that the traditional usage of the metric prefixes is more widely recognized. However, I feel this is trivial since the binary abbreviations (i.e. KiB, MiB, GiB, as opposed to KB, MB, GB, respectively) are very similar to their metric counterparts, the difference will not be noticed by most readers, but it does a lot in the way of accuracy for this somewhat confusing matter. In any case, the current state of the article is inconstistant in its use of IEC binary and metric prefixes, and something should be done either way. Please post your comments either supporting or objecting to this, I didn't want to make this kind of an edit without first consulting some others. -- uberpenguin 18:10, 2005 Mar 28 (UTC) ---- Hmm, would anyone be willing to create and/or add a schematic of the interior of a hard drive? I was wondering what typical random access times might be for various types of drives. I just ran a benchmark program on my HD and I was wondering how it compared to others. KM Typical current mass-market drives have ''seek'' times of around 9ms. Add just over 4ms latency to that (for a 7200 RPM drive) and you have an average access time of about 13.5ms. A seriously high-perforance drive has a seek time of under 4ms and latency of 2ms - i.e., 6ms average access. But these drives sacrifice capacity to achieve their very high performance, require a SCSI interface, and are fairly expensive. Tannin Tannin, any particular reason for reverting my change to an auto-generated thumbnail? There's really no reason to have separate thumbnail images anymore, and that particular image has already been listed on Votes for Deletion after being replaced at Computer storage. DopefishJustin 03:44, Apr 26, 2004 (UTC) Yes Justin. It looks terrible, and defaces a perfectly good photograph. If

    Hard Disk Platter


    A hard disk platter is a component of a hard disk drive. All hard drives contain one or more hard disk platters, which are used to actually hold the data. They are composed of two main substances: a substrate material, which forms the bulk of the platter and gives it structure and rigidity, and a magnetic media coating which actually holds the magnetic impulses that represent the data. Hard disks get their name from the rigidity of the platters used, as compared to floppy disks and other media which use flexible platters, which aren't actually even considered platters. The platters are where the data is recorded. For this reason the quality of the platters and particularly, their media coating, is critical. The surfaces of each platter are precision machined and treated to remove any imperfections, and the hard disk itself is assembled in a clean room to reduce the chances of any dirt or contamination getting onto the platters. Category:Rotating disc computer storage media

    Hard Disk Platter


    Regarding the examples of terminology misuse in the article:
  • they seem out of place in this article, as they talk mostly about disks not disk platters
  • they are technically nit-picky: common usage encompasses all of the definitions
  • they only admonish certain usages without specifying the correct usages
  • they read much like a word usage handbook and are out of place in wikipedia (?) I think they should be removed - mimirzero 02:36 Sep 13, 2002 (UTC) Does this even need its own entry? Hard disk seems an adequate place to discuss the makeup of platters. --Fubar Obfusco


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    Hard Disk Enclosure
    • Hard Disk Enclosure

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