Michael J. Mahon wrote:
oz390gta wrote:I have just got my hands on a box of 5.25" DS,HD floppy discs. I was hoping to format them as plain old 140k disks but when I try to format them the format fails. The physical format of the disks looks the same as SD disks. Is there anyway of using these disks?The oxide formulation used in 5.25" HD disks is magnetically incompatible with Apple (or third party) 5.25" drives, which were designed for SD or DD disks. They cannot be formatted or written on an Apple II.
Or, worse, will _appear_ to have been formatted and written to, only to lose data when it's time to read things back. It's been discussed many times on this group, but the HD disks have a much higher coercivity. In other words it takes a stronger magnetic field to saturate the domains, implying the need for more write current than the Apple II drive electronics can muster.