Disk
For mathematical usages, see Disk (mathematics).
1. Disk: Before the computer revolution, the term disc frequently referenced an analogue disc record: a flat vinyl recorded audio storage device, designed for playback on a gramophone (phonograph in American English). Compact discs have largely rendered the technology obsolete, except amongst audiophiles who specialise in using various sound technologies. And the term disc is also common for other flat, circular things, such as the Frisbee flying disc. Additionally, the term disc is also used to describe disk-shaped video media, including Laserdisc, DVD, Advanced Optical Disc, Blu-ray Disc.
Early BBC technicians differenciated between disks (in-house transcription records) and discs (the colloquial term for commercial gramophone records, or what the BBC dubbed CGRs).
In the minutiae of computer jargon, there also exists a distinction in spelling between what is called a disk and what is called a disc.
Simply put, disks are any storage media which utilize electromagnetic platters to store data. They are susceptible to data loss when placed near magnets, and comprise the following family of storage media:
- Floppy disks
- Hard disks
- Compact discs
- DVDs
- Advanced Optical Discs
- Blu-ray Discs
- Minidiscs
- Laserdiscs
- WORMs
One reason for the distinction is perhaps that the compact disc was invented by Philips, a European company (hence using the British English spelling, disc), whereas the hard disk was invented by IBM, an American company (using the American English spelling, disk). The distinction is mostly found in hardware documentation and is rarely maintained in software documentation for users, where disk is almost always preferred in the interest of consistency. More recently, the disc term is frequently applied to disk-shaped video formats including DVD and emerging video formats such as Advanced Optical Disc and Blu-ray Disc.
However, the disc term is not always consistently used, even with DVD. Google, for example, provides similar number of search results for both Digital Versatile Disk and Digital Versatile Disc, both of which are commonly-used expansions of the acronym DVD.
Another reason, explained in more detail in the external link, is that the audio field typically uses disc, whereas computer circles prefer disk, especially for magnetic media. The CD was originally used solely for its audio applications. After the rise of the CD, some audiophiles began calling phonograph records black discs.
External link
2. Disc:
Each vertebra in the cervical, thoracic and lumbar spine has an intervertebral disc above and below that functions as an axial force absorber and allows some degree of flexion, extension and rotation, and is therefore a joint. Each disc is made of an outer ring, named the annulus fibrosus which is a semi-rigid tissue, and an inner core named the nucleus pulpus, a gelatinous matter made mostly of water, which functions as the shock-absorbing segment. The annulus keeps the nucleus pulpus in place and contributes to the spine's stability,. Often, the nucleus extravasates out through the annulus to cause what is commonly known as a ruptured disc, a condition that may be corrected by one of a few ways: discectomy (percutaneous suction of the nucleus), decompression (removal of the extravasated segment) and fusion - the insertion of bone graft into the intervertebral space with or without vertebral fixation ("pedicle screws") and installment of metal implants that improve support.