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Comparison of various optical storage media. This article compares the technical specifications of multiple high-definition formats, including HD DVD and Blu-ray Disc; two mutually incompatible, high-definition optical disc formats that, beginning in 2006, attempted to improve upon and eventually replace the DVD standard.
Those 74 minutes come from the maximum playtime that the Red Book (audio CD standard) specifies for a digital audio CD (CD-DA); although now, most recordable CDs can hold 80 minutes worth of data. The DVD and Blu-ray discs hold a higher capacity of data, so reading or writing those discs in the same 74-minute time-frame requires a higher data ...
DVD+RW: rewriteable DVD defined by DVD+RW Alliance; DVD-RAM rewriteable, capable of random write access, not generally format-compatible with DVD; Blu-ray Disc: DVD successor, capable of high-definition video [1] BD-R: WORM Blu-ray Disc by the Blu-ray Disc Association; BD-RE: rewriteable BD; HD DVD: failed HD format defined by the DVD Forum [2]
For comparison with analogue media, the pitch of the spiral of a 240-groove-per-inch long-playing record and a Laserdisc are 106 μm (66 times the CD track pitch) and 4.6 μm (2.9 times), respectively. The tip of a 0.7-mil stylus has a diameter of 18 μm (11 times that of the CD laser spot). Data is from , , and .
The results of the power tests are stored in a Recording Management Area (RMA), which can hold up to 7,088 calibrations (in DVD-R). The disc can not be written to after the RMA becomes full, although it may be emptied in RW discs. CD-R, CD-RW, DVD-R, DVD+R, DVD-R DL, DVD+R DL, DVD+RW and DVD-R all have a PCA.
Comparison of several forms of disk storage showing tracks (not to scale); green denotes start and red denotes end. * Some CD-R(W) and DVD-R(W)/DVD+R(W) recorders operate in ZCLV, CAA or CAV modes. The digital data on a CD begins at the center of the disc and proceeds toward the edge, which allows adaptation to the different sizes available.
An optical disc is designed to support one of three recording types: read-only (such as CD and CD-ROM), recordable (write-once, like CD-R), or re-recordable (rewritable, like CD-RW). Write-once optical discs commonly have an organic dye (may also be a ( phthalocyanine ) azo dye , mainly used by Verbatim , or an oxonol dye, used by Fujifilm [ 4 ...
CD-ROM drives are rated with a speed factor relative to music CDs. If a CD-ROM is read at the same rotational speed as an audio CD, the data transfer rate is 150 Kbyte/s, commonly called "1×" (with constant linear velocity, short "CLV"). At this data rate, the track moves along under the laser spot at about 1.2 m/s.