Re: Platinum 5.25" drive problem

[mjmahon@aol.com (Michael J. Mahon)]

David Wilson wrote:

>mjmahon@aol.com (Michael J. Mahon) writes:
<snip>
>>The only exception would be using a SuperDrive to write an 800K
>>floppy, in which case only about half the 800K track width would
>>actually be erased and written.  (This is the problem in the PC world
>>when an HD 5.25" drive is used to write to a diskette formatted on
>>a lower density drive.)  Even then, there is no problem until the disk
>>is taken back to a lower density drive to be read.  The lower density
>>drive's wider head will read both the unerased old data and the newer,
>>narrower data, resulting in an I/O error.
>
>This is incorrect. All Mac and PC 3.5" drives are 80 track. All that
>changes is the bit density (and number of sides in the case of old 400KB
>MFS disks). The 1.2MB HD 5.25" drive did have this problem when writing
>to 360KB DD 5.25" disks. 1.2MB drives are 80 track, 360KB/180KB drives
>are 40 track.

Thanks, David, for setting me straight.  ;-)

I was confusing the 3.5" HD situation with the 5.25" one.

The good news is that this effectively eliminates the 3.5" "exception" I
was concerned about.  So, remanent off-track magnetization would
never be an issue for an Apple disk or drive (since HD 5.25" media
is manifestly incompatible with Apple 5.25" drives).

-michael

 Email:  mjmahon@aol.com
 Home page:  http://members.aol.com/MJMahon/