Re: High and Double density floppies

[nathan@cco.caltech.edu (Nathan Mates)]

In article <dgaxiola.12.006C140A@mit.edu>,
David Gaxiola <dgaxiola@mit.edu> wrote:
>In article <jolomoCLL3w2.67G@netcom.com> jolomo@netcom.com (Joe Morris) writes:

>Don't disk ][ drives need hard sectored floppies?  There's a small
>hole to the right of the main hole in the center of the disk.  As you
>rotate the disk by hand you'll notice that there's a small puncture in
>the disk that you can see through every now and then.  Soft sectored
>floppies (I think) have this hole only once.  Hard sectored disks have
>this hole several times.  Older disks needed to see these holes many
>times to get in sync.  Newer, high density disks, only have a single
>hole and won't work with the old disk ][ drive.  Is this correct or is
>my memory bad?

   (Apologies for reformatting this; some of your lines were real near
80 cols, so quoting them caused line wrap). Anyhow, you aren't quite
right. Other disk drives _before_ the AppleII needed either 1 or 16
hard sectors.... The Apple II drive uses totally soft sectoring, that
is, the info on the disk tells the computer where the sector is, and
the like. Therefore, if doesn't matter how many holes, if any, there are
in the radius for these timing holes. Holes in the main part of the
disk are another matter. :)

Nathan