(RHK) Somehow this doesn't sound right (and / or is not very clear / intuitive) to me--ToDo: Investigate and rewrite as appropriate.

Starting to rewrite

A typical hard drive consists physically of one or more circular disk of magnetic media which rotate about a central axis (think of a stack of CDs).

Electromagnetic read / write heads are attached to a multilevel arm assembly that can move across the radius of the disks.

There is (iirc) a read / write head assembly positioned to ride near the top and bottom of each disk. (There might be one less than that, instead, one that is a read-only magnetic or optical head to use in positioning the heads and start and end of sectors more precisely.)

The disks spin and the multilevel arm carrying the read / write heads moves laterally across the disks to read or write to the parts of the disk that can hold data.

Really, this would probably be easier to understand with a picture or two--I should search for some and link them here, or just refer you to a better explanation somewhere...

/Starting to rewrite

Hard Drive Geometry: The hard drive geometry of the disk is specified as:

• The number of cylinders that the disk contains;
• The number of tracks per cylinder (same as the number of heads);
• The number of sectors per track; and,
• The size of each sector (in bytes).

A typical hard drive consists physically of one or more circular platters which rotate about a central axis

The drive platters are divided into cylinders, which is the area of each platter which can be accessed without moving the heads. A cylinder is a barrel-shaped cross section of a disk, consisting of a circular strip from each side of each platter. The part of a cylinder which is the circular strip on a single latter is called a track.

Contributors

• JosephKmiec - 19 Jan 2002
• (RHK) RandyKramer - 2014-12-23
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