26-05-2012, 01:52 PM
Introduction of MiniDisc (MD)
[attachment=23159]
A MiniDisc (MD) is a magneto-optical disc-based data storage device initially intended for storage of up to 74 minutes and, later, 80 minutes, of digitized audio. In the form of Hi-MD, it has also developed into a general-purpose storage medium.
MiniDisc was announced by Sony in September 1992 and released that November for sale in Japan and in December for the USA and Europe.[1] The music format was originally based exclusively on ATRAC audio data compression, but the option of linear PCM digital recording was later introduced to attain audio quality comparable to that of a compact disc. MiniDiscs were very popular in Japan but made a limited impact elsewhere.[2]
Market history
Sony's MiniDisc was one of two rival digital systems introduced in 1992, that were both targeted as a replacement for the Philips analog cassette audio tape system: the other was Digital Compact Cassette (DCC), created by Philips and Matsushita. Sony had originally intended for Digital Audio Tape (DAT) to be the dominant home digital audio recording format, replacing the analog cassette. Unfortunately, due to technical delays, DAT was not launched until 1989, and by then, the U.S. dollar had fallen so far in relation to the yen, the introductory DAT machine Sony had intended to market for about $400 in the late 1980s now had to retail for $800 or even $1000 to break even, putting it out of reach for most users.
Relegating DAT for pro use, Sony immediately set to work to come up with a simpler, more economical digital home format. By the time Sony came up with MiniDisc in late 1992, rival Philips introduced a competing system, DCC (the digital compact cassette). This created marketing confusion very similar to the Beta vs. VHS battle of the late 1970s and early 1980s. Sony attempted to license MD technology to other manufacturers, with JVC, Sharp, Pioneer, Panasonic and others all producing their own MD systems. However, non-Sony machines were not widely available in North America, and companies like Technics and Radio Shack tended to promote DCC instead.
Design
The disc is permanently housed in a cartridge (68×72×5 mm) with a sliding door, similar to the casing of a 3.5" floppy disk. This shutter is opened automatically by a mechanism upon insertion. The audio discs can either be recordable (blank) or premastered. Recordable MiniDiscs use a magneto-optical system to record data. A laser heats one side of the disc to its Curie point, making the material in the disc susceptible to a magnetic field. A magnetic head on the other side of the disc alters the polarity of the heated area, recording the digital data onto the disk. Playback is accomplished with the laser alone: taking advantage of the Faraday effect, the player senses the polarisation of the reflected light and thus interprets a 1 or a 0. Recordable MDs can be recorded on repeatedly; Sony claims up to one million times. As of May 2005, there were 74 minute and 80 minute discs available. 60 minute blanks, which were widely-available in the early years of the format's introduction, were phased-out long ago and are rarely seen.
[attachment=23159]
A MiniDisc (MD) is a magneto-optical disc-based data storage device initially intended for storage of up to 74 minutes and, later, 80 minutes, of digitized audio. In the form of Hi-MD, it has also developed into a general-purpose storage medium.
MiniDisc was announced by Sony in September 1992 and released that November for sale in Japan and in December for the USA and Europe.[1] The music format was originally based exclusively on ATRAC audio data compression, but the option of linear PCM digital recording was later introduced to attain audio quality comparable to that of a compact disc. MiniDiscs were very popular in Japan but made a limited impact elsewhere.[2]
Market history
Sony's MiniDisc was one of two rival digital systems introduced in 1992, that were both targeted as a replacement for the Philips analog cassette audio tape system: the other was Digital Compact Cassette (DCC), created by Philips and Matsushita. Sony had originally intended for Digital Audio Tape (DAT) to be the dominant home digital audio recording format, replacing the analog cassette. Unfortunately, due to technical delays, DAT was not launched until 1989, and by then, the U.S. dollar had fallen so far in relation to the yen, the introductory DAT machine Sony had intended to market for about $400 in the late 1980s now had to retail for $800 or even $1000 to break even, putting it out of reach for most users.
Relegating DAT for pro use, Sony immediately set to work to come up with a simpler, more economical digital home format. By the time Sony came up with MiniDisc in late 1992, rival Philips introduced a competing system, DCC (the digital compact cassette). This created marketing confusion very similar to the Beta vs. VHS battle of the late 1970s and early 1980s. Sony attempted to license MD technology to other manufacturers, with JVC, Sharp, Pioneer, Panasonic and others all producing their own MD systems. However, non-Sony machines were not widely available in North America, and companies like Technics and Radio Shack tended to promote DCC instead.
Design
The disc is permanently housed in a cartridge (68×72×5 mm) with a sliding door, similar to the casing of a 3.5" floppy disk. This shutter is opened automatically by a mechanism upon insertion. The audio discs can either be recordable (blank) or premastered. Recordable MiniDiscs use a magneto-optical system to record data. A laser heats one side of the disc to its Curie point, making the material in the disc susceptible to a magnetic field. A magnetic head on the other side of the disc alters the polarity of the heated area, recording the digital data onto the disk. Playback is accomplished with the laser alone: taking advantage of the Faraday effect, the player senses the polarisation of the reflected light and thus interprets a 1 or a 0. Recordable MDs can be recorded on repeatedly; Sony claims up to one million times. As of May 2005, there were 74 minute and 80 minute discs available. 60 minute blanks, which were widely-available in the early years of the format's introduction, were phased-out long ago and are rarely seen.