Ah...those were the days. I still have a bunch of those with software on them. I wonder if they are any good.
I stopped notching after I disassembled my 5 1/4" drive, found the optic sensor that finds the read/write notch and installed a toggle switch on it. Complete with a red/green LED that would show read only or writeable status.
Way back when my personal computer was a Leading Edge and the only computer in the office I had ordered SuperCalc spreadsheet software on 5 1/4” diskettes to be addressed “Personal”.
The new office mgr, whose only experience had been in non-profits opened the package stapled a routing slip through disk and smashed the HD self inking date stamper leaving four indents on the disk. Totally useless.
A phone call explaining my problem resulted in hilarious laughter and a promise to FedEx a replacement to my home.
Said office mgr was fired a month later after proving she has zero understanding of standard office procedures and our particulr stds described in our manual...too busy to RFTFM.