Floppy disk sizes ( was Re: Compaq Portable III fails POST? )

[Chuck Guzis]

On 8/30/2006 at 10:35 PM ard at p850ug1.demon.co.uk wrote:

>Early 3.5" disks had a manual shutter, you had to slide it open before 
>inserting the disk in the drive, and squeeze the corner of the disk to 
>close it after ejecting the disk. Drives designed for those disks only 
>couldn't take the now-standard disks with automatic shutters because they 
>lacked the lever to open the shutter. 

Was this universal?  My Sony 2/3 height drive (40 cylinder, single side)
will accept the shuttered disks just fine and it's about as early a 3.5"
drive as one can find.

Cheers,
Chuck