On Sat, May 7, 2016 at 1:19 PM, Seth Morabito <li...@loomcom.com> wrote: > I have reason to believe that the CDC 9428 and 9429 are identical > except that the 9429 is jumpered for 80 tracks and the 9428 is > jumpered for 40 tracks... but I'm not 100% sure.
They would have to have different heads, if the 40 track model was standards-compliant and industry-compatible. A head suitable for 80-track use doesn't write a wide enough track to reliably write to a 40-track disk that has been written with a normal head. It's likely that the electronics is identical other than the jumper, and possibly the values of some passives.
