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From: hammen@gumby.UUCP (Robert Hammen)
Newsgroups: net.micro.mac
Subject: Re: HFS compatability and Software backup - Simple solutions
Message-ID: <45@gumby.UUCP>
Date: Thu, 23-Jan-86 18:16:37 EST
Article-I.D.: gumby.45
Posted: Thu Jan 23 18:16:37 1986
Date-Received: Sat, 25-Jan-86 07:40:46 EST
References: <1636@Shasta.ARPA> <348@ccivax.UUCP> <1667@Shasta.ARPA>
Distribution: net
Organization: U of Wisconsin CS Dept
Lines: 24
Summary: write-protected disks

In article <1667@Shasta.ARPA>, gus@Shasta.ARPA writes:
> > > unacceptable this would be. (You DO write-protect all of your master disks,
> > > don't you?)
> > 
> > I was just wondering... An article on the net several months ago hinted that
> > write-protecting a disk (with the tab in the upper left corner) didn't REALLY
> > protect the disk; that it was up to the software to ask the OS if the disk
> > was locked; that if the s/w didn't ask, the disk could be written to whether
> > or not it was locked.    DOES ANYONE IN NETLAND KNOW IF THIS IS TRUE?????
> > 
> > 
> > Sam Mantel -- Roch, NY
> 
> ...And an article from Apple a few days later said that indeed, the disk IS
> write-protected in hardware as well as software.

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