On Feb 12, 2021, at 3:12 PM, jim stephens via cctalk <cctalk at classiccmp.org> wrote: There was a company who made a drive with glass media that a friend of ours repped for. It used a repurposed CD head which was driven hard enough to write their media. it was sold as being able to be written and locked such that it couldn't be further modified if need be. The nuclear security people were interested, but ultimately passed due to the size off the player, and the need for very long term access to the technology.

On 2/12/21 12:21 PM, Paul Koning via cctalk wrote: WORM appeared in the 8" and 12" disc format as well, IIRC. --Chuck

On 2/12/2021 11:46 AM, Chuck Guzis via cctalk wrote: https://books.google.com/books?id=x1yigTsvZxsC&lpg=RA1-PA475&ots=5n… There was a company who made a drive with glass media that a friend of ours repped for. It used a repurposed CD head which was driven hard enough to write their media. it was sold as being able to be written and locked such that it couldn't be further modified if need be. The nuclear security people were interested, but ultimately passed due to the size off the player, and the need for very long term access to the technology. The floppies you hear about (off topic) containing security information are written with a process that makes it very hard if not impossible to alter them w/o destruction of the data at the remote end. The worm drives had a way to write, then alter by putting in an update marker on the media. You had to work your way to the last version of the directory and work your way back to find all the files. Versioning was used to allow updates. The software package could go back thru the data and allow you to see all the updates if need be. Once you got to full, the media would be marked locked with a special area at the inner tracks and from there on would not be updateable. Mot sure if this is the same operation or not. They used an regular ESDI interface on the drives they gave us for eval. IIRC basic read and writes could happen on the media, but special drivers could be used to make it look more like a flat FAT type file from to such as Dos or Windows at the time. FAT from the standpoint of the software api, file name and the like. The structure on the disk was not necessarily physically compatible. We got an eval unit because I had bought the necessry ESDI controller, and we could use the drive. ESDI was not common at the time and was not widely available at that time. IIRC we had 386 systems AT bus type systems. I had a sample disk at some point, not sure where it went. I sent a big pile of manuals and specs to Al last year, might have had the stuff from whoever we had the drive from in that pile if I still had it. My partner passed away about 2 weeks ago and would possibly have recalled who it was, but can't ask now. I'll try a scan of our contact files and see if "opti" anything shows up. thanks Jim