Re: How to destroy a 5.25 disk in Applesoft

[Don Bruder <dakidd@sonic.net>]

In article <lPOdnU36If46j4bZnZ2dnUVZ_s6dnZ2d@comcast.com>,
 "Michael J. Mahon" <mjmahon@aol.com> wrote:

> Jayson Smith wrote:
> > Hi,
> > A few weeks ago I wrote a little program in Applesoft.  It runs under DOS
> > 3.3 and will totally wipe out a 5.25 disk, to the point where it must be
> > reformatted to be usable under any OS.  I thought I'd share it here just in
> > case anybody is interested.  Note, this doesn't check for write protect
> > status, so if the hardware supports this it would totally destroy a write
> > protected disk!  I don't have any write protected disks I really want to try
> > this on, so be very careful with this program!
> 
> It's easy to temporarily write-protect one with a sticker
> over the notch for experimentation.
> 
> IIRC, the Disk ][ Controller will not write to any write-protected
> disk, regardless of whether the software checks it or not.

Truth. The write circuit doesn't engage unless the hardware reports a 
lack of write-protection. It'll go through the motions, but nothing 
actually gets written. Much like the "simulation mode" most CD-burning 
software uses - It does everything as if it were writing, without the 
actual write signals getting to the head to operate the laser. Ditto for 
the Apple's floppies - It'll go through the motions, but the write 
signals get blocked in hardware before they reach the head, so nothing 
actually happens.

-- 
Don Bruder - dakidd@sonic.net - If your "From:" address isn't on my whitelist,
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