A CD-ROM (abbreviation of Compact Disc Read Only Memory ) is a Compact disk containing all numerical kinds of Donnée S intended to be read by a Ordinateur. The CD-ROM is an evolution of the original compact disk, which is dedicated to the musical numerical data planned for a Lecteur of CD of Hi-fi system. The cédéroms supplanted the Disquette S in the distribution of the Logiciel S and other computer data.

Etymology

CD-ROM is the abbreviation of Compact Disc Read-Only Memory , that is to say Compact disk Read-only memory . The abbreviation CD is commonly used in French, although it is the abbreviation of Compact Disc and that in French one uses rather the translation compact disk . One can note that the logo Compact Disc DIGITAL Audio is common on the compact disks.

Francization

The term cédérom is the official Francization by the French Academy of CD-ROM , which comes simply from the phonetic reading of these initials of origin English E. Since then (1996), cédérom and CD-ROM into tiny are regarded as common nouns in French, and thus take an S in the plural.

Description

A CD-ROM contains only nonmodifiable data: it can be read by a Lecteur of optical disk (Lecteur CD), but cannot be written by a engraver.

It is an optical disk in Plastic, approximately 12 cm diameter for 1,2 mm thickness. That makes a very light support, being able to contain of 650 or 700 Me of computer data, that is to say respectively 74 or 80 minutes of audio recording in the format of data of the original compact disks (16 bits, stereophony, not compressed, 44.100 Hz).

One also finds discs of higher capacities, but their reading can pose problem.

See also: Disc compact#Capacity of storage and speed

Limitations

Like all Numerical information support S , it allows an excellent theoretical conservation of the data, and as a disc read without contact (by the Laser of the reader), it is not subjected to direct mechanical wear.

In practice, it is in fact rather moderately reliable: if it is supposed to preserve the data during a hundred of years, this argument on-was sold and reality would rather approach the ten, even five years, even by surrounding the product of adapted protections. The plastic material is indeed sensitive to the radiations Ultraviolet S contained in the light, to the heat, and the stripes of surface (frictions during handling) which involve misreadings quickly, then total impossibility to read it.

Support with the contents

By extension term CD-ROM is employed to qualify the type of programs diffused on support CD-ROM. One speaks about cultural CD-ROMs or educational CD-ROMs…, gradually replaced today by DVD-ROM.

After a wave of important popularity in the middle of the Years 1990, the industry of the interactive contents on optical disk declining, is largely competed with by the diffusion on Internet.

Organization of the data

The data are engraved on the CD-ROMs according to different file systems:

There exist also images of the files systems " natifs" Operating systems hosts, like HFS for Mac OS.

See too

Related articles

cédérom CD-ROM

  • Compact disk for more details on the history, or the use and manufactoring processes.

  • GD-ROM for (not very known) the compact disks of great capacity of Yamaha.
  • CD-R/CD-RW for the recordable and rewriteable compact disks.
  • DVD and DVD-ROM (and not Dévédérom) for the technology of Optical disk succeeding the disc.
  • HD-DVD and Blu-ray Disc to get information about technologies succeeding the DVD.

External bonds

  • retrospective Glance on the cultural CD-ROMs

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