Hard Sectored Optical Discs (MO, PD, DVD-RAM)



Hi Guys,

Been a while since I’ve been around, but I just put up a blog post about hard sectored recordable optical discs which some readers may find rather interesting. Two of them are older technologies which pre-date recordable CD-R’s - the Magneto Optical Disc and Phase-change Dual Disc. I’ve also lumped in DVD-RAM, as it is relatively exotic and is a hard sectored format.

Please enjoy the post here: http://goughlui.com/2015/08/10/mega-tech-flashback-writable-optical-discs-mo-pd-dvd-ram/

  • Gough


Very interesting. :clap:

Nice to take a trip down memory lane back to the early 90s, reminiscing how I became an optical disc freak (although it would be another decade before I found this place, full of likeminded individuals). I used to endlessly re-read computer magazines, especially the adverts, drooling over (metaphorically, honest ;)) any mention of MO & PD drives with prices far beyond my means.

After releasing the first laptop with a built-in CD-Rom drive, Panasonic went on to produce a version with a PD drive. That was far more exciting than Canon’s built-in printer.

My fantasy computer continued to feature Fujitsu 3.5" MO and Panasonic PD drives long after the first practical CD writers hit the market (although there was room for one of those as well). Then when DVD-Ram was released…


Glad to hear from a fellow enthusiast that remembers such formats. I’ll admit that I was also one to stare at the drives at the back of computer magazines, with them costing about AU$1200 at the time. At the time, CD-ROMs were somewhat widespread, and I remember myself somewhat prophetically proclaiming that “those CD’s won’t last. You can’t even write to them. MO cartridges are the future - almost infinite rewritability and with much better safety for the disc.” I laugh now, but sometimes, I feel sad that the technically superior technology didn’t quite make it to be adopted by the masses.

I wasn’t even aware of PD at the time, as MO really dominated the “Optical Drive” category. Looking back, the name of Optical Drive and Optical Disc Cartridge was very non-descript - it was as if they didn’t anticipate any other technologies would come along.

Anyhow, I did participate in the CD, DVD, DVD-RAM, and Blu-Ray era … which might mark the end of Optical media for consumers in the end.

One of my earliest memories of recordable CDs was handling a Sony 63 minute CD-R that had been recorded by an educational institution as a back-up, which had gold foil and probably some cyanine dye for a really deep, rich, dark green. Sadly, such early “pre-74-minute” era CD-Rs are very rare to see … just as were 2.6Gb per side DVD-RAM, 3.95Gb DVD-Rs, DVD-R for authoring (using a different laser wavelength), and HD-DVD-R (seen online, but not in the flesh).

Enough rambling though …