I have a vague memory that PD stands for Phase-D?????. Where a laser heats a spot on the disk and a magnetic field changes the phase something or other of the heated spot. After it cools the difference in the magnetic hossitz can still be read. It makes the disk extremely reliable after it is written, because it cannot be erased without heating it again.
These were in competition with Magneto Optical disks back in the 90s.
They are a removable media similar to ZIP or magneto optical, but the technology used by the disks is very different.
I remember several articles mentioning them in MacUser and MacWorld round ups of removable media storage devices. If you found an article in one of those magazines which compared the Pinnacle Micro Sierra 1.3 GB drive to other drives, you'd probably find that at least one of the other drives was a PD drive.
That might give you enough to search on. The Sierra was a Magneto Optical but it was contemporaneous with some of the PD drives.
These were in competition with Magneto Optical disks back in the 90s.
They are a removable media similar to ZIP or magneto optical, but the technology used by the disks is very different.
I remember several articles mentioning them in MacUser and MacWorld round ups of removable media storage devices. If you found an article in one of those magazines which compared the Pinnacle Micro Sierra 1.3 GB drive to other drives, you'd probably find that at least one of the other drives was a PD drive.
That might give you enough to search on. The Sierra was a Magneto Optical but it was contemporaneous with some of the PD drives.