Acronym for "Read only memory". It's memory which can't be modified once recorded, like with a CD-ROM.

          When one talks about memory here one talks about 0s and 1s which have been written into some support and to which one can acces at least in reading. For example in a CD-ROM the 0s and 1s fit with minute bumps and holes carved at the surface of the disk.

          The recordings on a hard disk are magnetic and can be modified after original recording, which is not the case for a CD-ROM.

          In the case of a CD-RW, one can modify the recordings of that special CD with a burner. The RW stands for ReWritable.

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