Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!ucsd!ucbvax!ADMIN.HumberC.ON.CA!GRAY From: GRAY@ADMIN.HumberC.ON.CA (Kelly Gray) Newsgroups: comp.sys.apple2 Subject: Re: Write Protection Message-ID: <90Jun5.065940edt.57687@ugw.utcs.utoronto.ca> Date: 5 Jun 90 10:50:40 GMT References: Sender: daemon@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 10 As far as I'm aware of, write protection on Apple drives has always been done BOTH in the hardware and in the software. The earliest DOS manual I have ever seen (DOS 3.2!) indicates that the drive hardware in a Disk II drive has not changed since it was introduced. The write protect sensor in the Disk II is used to create the signal that is sent back to the computer, and it also disables the write circuitry entirely, making a write to a write-protected floppy disk physically impossible unless the drive analog card is defective. Kelly Gray (GRAY@ADMIN.HUMBERC.ON.CA)