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A '''hard drive''' is the large memory storage mechanism of a typical computer.  It is typically a set of mechanical rotating disks with read/write "heads" that "fly" at sub-micron heights above them, reading and writing data magnetically.  The heads typically "seek", moving over the disk's surface to access the desired circular track on the disk.  This is in contrast to the [[RAM]], random access memory that the computer accesses on a nanosecond-by-nanosecond basis.  The disk drive is typically more than a million times slower than the RAM, but with much larger data capacity.  It also has the property that its data persists when the computer is turned off, while RAM often loses its data.  When the computer is operating, it requires access to both the RAM and the disk.  The [[operating system]] performs operations to read data from the disk into the RAM, and proceeds from there.

A '''hard drive''' is an older digital storage device for computers.  It is typically a set of mechanical rotating disks ("platters") with read/write "heads" that "fly" at sub-micron heights above them, reading and writing data magnetically.  The heads typically "seek", moving over the disk's surface to access the desired circular track on the disk.  This is in contrast to the [[RAM]], random access memory that the computer accesses on a nanosecond-by-nanosecond basis.  The disk drive is typically more than a million times slower than the RAM, but with much larger data capacity.  It also has the property that its data persists when the computer is turned off, while RAM often loses its data.  When the computer is operating, it requires access to both the RAM and the disk.  The [[operating system]] performs operations to read data from the disk into the RAM, and proceeds from there.

The computer's programs and files are permanently stored on the disk.

The computer's programs and files are permanently stored on the disk.

A higher-performance interface is SCSI (Small Computer Systems Interface), configured as SAS (Serial Attached SCSI).  Such disks typically have higher performance (higher rotational speeds) than are found on ordinary laptops.

A higher-performance interface is SCSI (Small Computer Systems Interface), configured as SAS (Serial Attached SCSI).  Such disks typically have higher performance (higher rotational speeds) than are found on ordinary laptops.

[[Category:Computers‏‎]]

[[Category:Computer Hardware‏‎]]