HP-87 and HP-9122D

[Dave Frederickson]

(07-20-2019 08:42 AM)stephenpeterson Wrote:  I can INITIALIZE and use DSDD floppy disks with my HP-87, an HP-9121D disk drive and the PRM-85 ROM Emulator board.

You can initialize one side of a DSDD disc in a dual single-sided 9121D disc drive. DSDD discs are more readily available and there's no point in trying to find single-sided media.

Trivia Note: DSDD and SSDD media were manufactured the same, it's just that the second side of single-sided media wasn't tested.

Don't try to format HD media as DSDD as the magnetic properties are not the same.

Of note, for the 3.5" HP discs pictured on HPMuseum.net, SSDD discs are blue, DSDD discs are gray, and DSQD (HD) discs are black.

Dave