Phase-change Dual
The phase Writer Dual ( PD) was the first generation of optical storage solution on the basis of the phase - change technology.
When phase Writer Dual there is no uniform spelling. Some will also be called phase-change disc, because inside the cartridge a plastic disk (English: disc) is located. Other well-known synonyms of PD are the popular variants PD medium, PD disk (german PD disc ), PD - or PD cartridge drive.
History
The PD came out in 1995 by Panasonic and was offered by the manufacturers NEC, Panasonic, Plasmon, TEAC and Toray.
The PD has been displaced a short time after her release from the CD- RW, which is also based on the phase - change technology. Although PD is clearly superior to the CD- RW in terms of being rewritten, data security and manageability, the CD -RW, however, was marketed attractively priced and offensive. For rapid displacement of the PD also added, that many customers at the time the difference between the operating concepts, creating a CD -RW disc by burning software on the one hand and the removable hard disk like using a PD on the other hand, was not aware of.
The manufacturers tried from 1995 to 1998 to increase the market share of the PD with so-called combi drives. This combo drives could read or describe next to the PD and CD- ROM and CD -RW. Ultimately, these efforts of manufacturers were in vain. Since 2001, PD- drives and their PD discs in trade are virtually extinct. The extinction of PD was done silently because the drives of the first generation of DVD - RAM were backward-compatible with PD.
Specification of the storage devices
In the following, only the information is presented, which are of general interest. Pure technical details on over 100 pages in the chapter " norms and standards " can be seen (see below).
The PD medium has a memory capacity of 650 MB ( megabytes ) and is only available in a cartridge. The actual volume is a plastic disc diameter of 120 mm. Visually, a PD medium is easily confused with a MO medium or a DVD- RAM cartridge.
Devices
- Matsushita LF -1094: PD / CD-ROM combination - drive the first hour (1995 ), SCSI
- TEAC PD- 518E: A CD -ROM drive, was that in addition to read and write also PD.
- Panasonic LF- D101, LF- D102, LF- D103, all three SCSI, and LF- D110 and LF- D111 both ATA: This five DVD -RAM drives of the first generation (DVD-RAM 1.0) were also able to read PD discs and describe.
Norms and Standards
- ISO / IEC 15485, based on the Standard ECMA- 240.