Tagged: Orange Book

Mini CD-R / CD-RW (1990s – )

Mini CD-R (CD-Recordable) and Mini CD-RW (CD-Rewritable) are 8cm versions of CD-R/CD-RW. They can hold anything from 156 MB (18 minutes of music) to 210 MB (24 minutes of music).

They can be written to in spindle-based or tray-loading CD-R / CD-RW burners (and read in spindle-based or tray-loading Compact Disc players) but there were also some devices that were specifically designed around the Mini CD-R/CD-RW.

One of these was a number of models in the Sony Mavica line of digital cameras. The first of these was the MVC-CD1000 released in 2000, which could record to Mini CD-Rs. Later models in the line (the last of which was released in 2003) could use either Mini CD-R or Mini CD-RW.

There was also a portable Mini CD-R burner called the Imation RipGo! that was introduced in 2001. This could burn MP3 files to disc, and also play them back. Sony also introduced a Mini CD burner (called the PhotoVault), allowing pictures to be saved from a Memory Stick, USB flash drive, or camera with a USB connection.

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Compact Disc-Recordable (CD-R) (1992 – )

Compact Disc-Recordable (CD-R) is an optical disc  format designed by Philips and Sony, and based on the Compact Disc. CD recorders became available in 1992 but were extremely expensive and it wasn’t until 1995 that they fell below $1000 (around £650).

CD-R discs can be used for audio or data recording, but only CD-R Audio discs can be used in standalone consumer audio recorders.

CD-Rs are a Write Once Read Many (WORM) medium, although the whole disk does not have to entirely written in the same session. Their specification is taken from the Orange Book standards. Properly written CD-Rs are fully compatible with audio (CD-DA) and data (CD-ROM) Compact Disc standards.

Standard CD-Rs are 120mm in diameter (although 8cm Mini CD-Rs are also available), and most can store 74 minutes of audio or 650 MB of data. Some CD-Rs have an 80 minute or 700 MB capacity, but anything over this means they are not fully compatible with CD standards.

A CD recorder writes data to a CD-R disc by pulsing its laser to heat areas of the organic dye layer. The writing process does not produce indentations (pits) – instead, the heat permanently changes the optical properties of the dye, changing the reflectivity of those areas. Various dyes have been used over the years, with cyanine being the earliest and less stable.

In general CD-Rs are expected to have an average life expectancy of 10 years. As well as degradation of the dye, failure of a CD-R can be due to the reflective surface. While silver is more widely used, it is more prone to oxidation. Gold-based CD-Rs do not suffer from this problem, but are more expensive.

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Preservation / Migration