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Stay on track

Mainstream ESDI drives use 34 to 36 sectors per track. Most (older) controllers cannot handle more than this number of sectors. Newer, higher capacity, drives use higher numbers of sectors per track. For instance, I own a 670 Mb drive that has 54 sectors per track.

In my case, the controller could not handle this number of sectors. It proved to work well except that it only used 35 sectors on each track. This meant losing a lot of disk space.

Once again, check the documentation of your hardware for more info. Going out-of-spec like in the example might or might not work. Give it a try or get another more capable controller.
Hard or soft sectoring

Most ESDI drives allow hard or soft sectoring to be selected using a jumper. Hard sectoring means that the drive will produce a sector pulse on the start of each new sector. The controller uses this pulse to tell when it should start to write or read.

Hard sectoring allows a selection of sector size (normally 256, 512 or 1024 bytes per formatted sector). FreeBSD uses 512 byte sectors. The number of sectors per track also varies while still using the same number of bytes per formatted sector. The number of unformatted bytes per sector varies, dependent on your controller it needs more or less overhead bytes to work correctly. Pushing more sectors on a track of course gives you more usable space, but might give problems if your controller needs more bytes than the drive offers.

In case of soft sectoring, the controller itself determines where to start/stop reading or writing. For ESDI hard sectoring is the default (at least on everything I came across). I never felt the urge to try soft sectoring.

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Сменил винт и контроллер. Он тоже определился как 34сект, но загрузился!!!!!!!!!!!!!
С ним все ОК.
А вот после изменения на 36секторов не грузится. Итак, решили, что наверное опечатка на сайте.

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