Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!UIAMVS.BITNET!AWCTTYPA
From: AWCTTYPA@UIAMVS.BITNET ("David A. Lyons")
Newsgroups: comp.sys.apple
Subject: Bredon's Write Protect CDA
Message-ID: <8902152347.aa02729@SMOKE.BRL.MIL>
Date: 16 Feb 89 06:06:37 GMT
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X-Unparsable-Date: Wednesday 15 Feb 89 7:12 PM CT

>Date:         Tue, 14 Feb 89 02:10:25 GMT
>From:         Bob Sherman <umigw!umbio!bsherm@HANDIES.UCAR.EDU>
>Subject:      Re: protecting hard drives

>There is a DA available for the GS written by Glen E Bredon that will
>write protect ALL devices at the same time. This included the RAM5 as
>well as hard drives etc. I don't know all where it is available, but
>I do know it is in the download section of Miami's Big Apple.

That DA works only with ProDOS 8.  It can be useful, but it's not as
good as hardware write-protection:  it can be bypassed if a program
goes right to the ProDOS entry points of the slots (calls Cn00+(CnFF)
with a WriteBlock command + block number on zero page).

>  Internet  -- bsherm%umbio@umigw.miami.edu
>  UUCP      -- {uunet!gould}!umbio!bsherm
>  Miami's Big Apple  305-948-8000  1200 baud  24 hours  8 years online

--David A. Lyons              bitnet: awcttypa@uiamvs
  DAL Systems                 CompuServe:  72177,3233
  P.O. Box 287                GEnie mail:    D.LYONS2
  North Liberty, IA 52317     AppleLinkPE: Dave Lyons