Re: High and Double density floppies

[dempson@swell.actrix.gen.nz (David Empson)]

In article <dgaxiola.12.006C140A@mit.edu>
dgaxiola@mit.edu (David Gaxiola) writes:
>
> Don't disk ][ drives need hard sectored floppies?

Nope.  Read on.

> 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.

All correct.  The holes are used to position the start of each sector
on a "hard sectored" floppy.  On a "soft sectored" floppy, the single
hole is used by some drives to position sector zero when the track is
formatted.

This does NOT include the Disk ][ or derivatives (UniDisk 5.25, etc.).
These drives do not even sense the hole.  Apple II 5.25" drives write
sector zero at an arbitrary position on the first track, and at a
fixed relative position on subsequent tracks (though this is not a
requirement, just how it turns out).

You can use either type of disk in a Disk ][.  The sectors will be
"soft" in either case.
-- 
David Empson                                                               
dempson@swell.actrix.gen.nz                                                
Snail mail: P.O. Box 27-103, Wellington, New Zealand