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From: espen@well.UUCP (Peter Espen)
Newsgroups: net.micro.mac
Subject: Re: HFS compatability and Software backup - Simple solutions
Message-ID: <635@well.UUCP>
Date: Mon, 10-Feb-86 19:59:32 EST
Article-I.D.: well.635
Posted: Mon Feb 10 19:59:32 1986
Date-Received: Wed, 12-Feb-86 07:46:29 EST
References: <1636@Shasta.ARPA> <348@ccivax.UUCP> <1667@Shasta.ARPA> <425@mmm.UUCP> <454@mmm.UUCP>
Distribution: net
Organization: Whole Earth Lectronic Link, Sausalito, CA
Lines: 42
Summary: It IS indeed a mechanical (not an optical) write-protect scheme.

In article <454@mmm.UUCP>, mrgofor@mmm.UUCP (Michael Ross) writes:
> In article <597@puff.UUCP> hammen@puff.UUCP (Zaphod Beeblebrox) writes:
> >In article <425@mmm.UUCP>, mrgofor@mmm.UUCP (Michael Ross) writes:
> >> In article <45@gumby.UUCP> hammen@gumby.UUCP writes:
> >> >
> >> >The way the protection works is if a sensor sees the little red light shine
> >> >through the hole of a locked disk, nothing gets written to the disk.  
> >> >However, I've been told that it is possible to instruct the IWM to turn off
> >> >the light, thereby making the disk writeable....
> >> >						Robert J. Hammen
> >> >						Manta Software Corp.
> >> >						U of Wisc. CS Dept.
> >> >						hammen@gumby.uucp
> >> 
> >> Then how come my Sony disks work? The write-protect mechanism on those
> >> diskettes doesn't include a hole going through the diskette - there is a 
> >> small tab that can be moved back and forth, but you can't see through the
> >> diskette in either mode.
> >> 
> >> 	--MKR
> > No, you don't seem to understand.  The tab that you slide back & forth IS
> > the hole that I'm referring to. (I never said the hole was in the actual 
> > media).  When the tab is moved so that you can see through the CASE of the
> > microdisk, then the disk is locked.
> >
> >						Robert J. Hammen
> 
> 	No, you don't seem to understand. The CASE does NOT have a hole
> in it. No matter where the tab is, you cannot see through the case. I know
> what you mean about the holes, but my point was that I think it must be
> mechanical rather than optical in nature because of the fact that some
> (not all) of my Sony diskettes do not have a hole all the way through.
> There is an easy way to check - I could just look at the damned drive
> and find out, but I'm too lazy. Besides, ungrounded speculation is fun.
> 
> 	--MKR
	My reality frame of reference states that the write-protection
scheme on the Mac/Sony 3.5" Single-sided drives is indeed mechanical, not
optical like on many of the older 5.25" and 8" drives that we all know and
don't miss.
	Peter Espen