dave@uunet.UU.NET (Dave Horsfall) (11/15/89)
In article <0007.8911071214.AA17820@ge.sei.cmu.edu>, kichler@harris.cis.ksu.edu (Charles Kichler) writes: | The advantage is hardware is difficult to modify via software. As of yet, | I haven't seen a program that can beat a write protect tab. I have heard a story, perhaps apocryphal, of a disk controller whose "write protect" mechanism merely set a bit in a register, which the software was supposed to check. Do you _know_ your write-protect tab really works? [Ed. This question was discussed a few times on VIRUS-L/comp.virus; the consensus was (after reviewing schematic diagrams) that the write protect mechanism on PCs (and clones thereof) and Macs is implemented in hardware and is thus not circumventable without hardware modifications. Unless someone can produce a definitive, reproducable piece of code that can prove otherwise, lets all please consider this to be the case.] Dave Horsfall (VK2KFU), Alcatel STC Australia, dave@stcns3.stc.oz.AU dave%stcns3.stc.oz.AU@uunet.UU.NET, ...munnari!stcns3.stc.oz.AU!dave
fin%uf.msc.umn.edu@vma.cc.cmu.edu (Craig Finseth) (11/17/89)
kichler@harris.cis.ksu.edu (Charles Kichler) writes:
...
Do you _know_ your write-protect tab really works?
[Ed. This question was discussed a few times on VIRUS-L/comp.virus;
the consensus was (after reviewing schematic diagrams) that the write
protect mechanism on PCs (and clones thereof) and Macs is implemented
in hardware and is thus not circumventable without hardware
modifications. Unless someone can produce a definitive, reproducable
piece of code that can prove otherwise, lets all please consider this
to be the case.]
I would like to confirm the "Ed." tack-on for IBM PCs, clones, and
Macs. However, early Apple ][s *did* implement this feature in
software.
I don't know for sure, but believe that later (=current) Apple ][s,
Ataris, and Amigas perform this function in hardware.
Craig A. Finseth fin@msc.umn.edu [CAF13]
Minnesota Supercomputer Center, Inc. (612) 624-3375