davidbrierley@HELIOS.NORTHEASTERN.EDU (06/05/90)
The follwing is an excerpt from the Virus-L Digest (Volume: 3
Issue: 105). Can someone, preferably from Apple, clarify where the
write protection mechanism is. It is my understanding that early
Apple disk drives had the write protection mechanism based in
software, while "newer" drives, including those of the present, have
the mechanism in hardware. Again, an official word from Apple would
be most welcome, especially if a year and serial number are given for
when the "new" disk drives (with hardware-based write protection)
were produced. If an Apple representative does answer, I'd appreciate
it if they cross-post the response to Virus-L at the "Reply To:"
address below; otherwise I can cross-post it myself. Thank you, in
advance (and I'm sorry if I have raised this issue a second time).
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Date: Fri, 1 Jun 90 15:49:44 EDT
From: "The Moderator Kenneth R. van Wyk" <krvw@CERT.SEI.CMU.edu>
Subject: VIRUS-L Digest V3 #105
Reply-to: VIRUS-L@IBM1.CC.LEHIGH.edu
VIRUS-L Digest Friday, 1 Jun 1990 Volume 3 : Issue 105
------------------------------
Date: Thu, 31 May 90 21:13:27 -0400
From: simsong@next.cambridge.ma.us (Simson L. Garfinkel)
Subject: write-protection viruses
Write protection on the Apple II computer is done in software; on this
machine a virus could overcome write-protection on a floppy disk.
I once used a program that "degaused" a floppy disk in 15 seconds or
so on the Apple II, even if the floppy disk was write protected.
------------------------------GRAY@ADMIN.HumberC.ON.CA (Kelly Gray) (06/05/90)
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.
<o_o>
Kelly Gray (GRAY@ADMIN.HUMBERC.ON.CA)jerryk@pro-tcc.cts.com (Jerry E. Kindall) (06/06/90)
In-Reply-To: message from davidbrierley@HELIOS.NORTHEASTERN.EDU Nope, write protection on the Apple II is in hardware. The software can choose to ignore the write protection signal and attempt to do its writing, but nothing will actually get written. _____ ||___|| Jerry Kindall | Internet: jerryk@pro-tcc.cts.com | o | 1139 Maryland | UUCP: nosc!crash!pro-tcc!jerryk |__O__| Grosse Pointe, MI 48230 | GEnie: A2.JERRY ALine: A2 Jerry
paul.l@gnh-applesauce.cts.com (Paul Langhorn) (06/13/90)
Well, any info you've heard about write protection being under software control is totally bogus. There are direct Smartport and hardware softswitches that when accessed will tell you if the disk is write protected or not. And if it is, the drive will simply NOT write to it. /+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+\ & & & Paul Langhorn INET:paul.l@gnh-applesauce.cts.com & & & & To Quote A Very Wise Creature: "Do... or Do Not; There Is No Try." & & & \+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+/ /+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+\ & & & Paul Langhorn INET:paul.l@gnh-applesauce.cts.com & & & & To Quote A Very Wise Creature: "Do... or Do Not; There Is No Try." & & & \+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+%+/