[cctalk] Re: Flipping an 8" diskette

On Wed, 31 Aug 2022, Liam Proven via cctalk wrote: Both 5.25" and 8" disks have a "cookie" that is coated on both sides ("single sided" disks only gurantee the quality of one side) BUT, it defintiely won't be a NOTCH! The children of the "bar napkin disk" (a well refuted origin myth) age were accustomed to being able to punch an extra WRITE-ENABLE notch in 5.25" diskettes to flip them over for Apple and Commodore, as the write enable notch was the only disk non-symmetry for THOSE machines. Other 5.25" machines, such as TRS80, hard sectored machines, 5150, etc. ALSO needed index holes punched in the jacket to complete their symmetry. ("Berkeley Microcomputer Flip-Jig" for marking the location was my first retail porduct; "PLUS" model also aligned center hole reinforcers). 8" disks used a Write PROTECT notch. adding a notch was to PREVENT them being writeable! SO, no notch punching required for flipping them. So, the FB kids should definitely punch a notch to keep them out of trouble :-) BUT, depending on the DRIVE, additional index holes may (or may NOT!) be needed. Single sided 8" drives could flip disks if the disk jackets were punched with symmetrical index holes. ("EIGHT INCH Berkeley Microcomputer Flip-Jig" (very rare) could mark those locations) Double sided 8" had the index hole in a different location than the Single sided disks! Single sided 8" disks could be converted into double sided 8" disks by adding index holes in the correct locations. ("EIGHT INCH Berkeley Microcomputer Flip-Jig" (very rare) could mark those locations) But, some double sided drives had TWO index hole sensors (light and photocell). THOSE drives could use single OR double sided disks! WITHOUT any extra holes! (and might be CONFUSED by a disk that had both SS and DS holes) OB_IRRELEVANT: On the "Computer Bowl" quiz show, Bill Gates' team was unable to answer a question of "WHERE is the write enable notch on an 8" disk?" !! Kids. keep 'em offa my lawn! -- Grumpy Ol' Fred cisin(a)xenosoft.com