OT: USB stick with write protect switch?

[Amedee Van Gasse (u2s)]

On Sat, October 10, 2009 22:16, Colin Law wrote:
> 2009/10/10 David N. Lombard <dnl at speakeasy.net>:
>> Amedee Van Gasse (on Ubuntu mailing lists) wrote:
>>> On Sat, October 10, 2009 18:29, Frans Ketelaars wrote:
>>>> On Sat, 10 Oct 2009 09:13:44 -0600, drew einhorn wrote:
>>>>
>>>>> The convenience of booting from a USB stick is great!
>>>>>
>>>>> It would be even better to be able to flip a switch on the stick and
>>>>> making it a read only device!
>>>>>
>>>>> Anybody know of a source?
>>>> This one
>>>> http://www.newegg.com/Product/Product.aspx?Item=N82E16820141488
>>>> has a write protection switch .
>>>
>>> Can anyone confirm that these "hardware" R/O switches always work in
>>> all
>>> circumstances and that there is no way whatsoever that software can
>>> ignore
>>> the write protect?
>>>
>>> Because I have read once that it was possible but I forgot to bookmark
>>> the
>>> source.
>>
>> It's entirely possible some USB keys with r/o switches don't work
>> reliably or can be circumvented. Â But, as they say in Perl, TIMTOWTDI
>> (there's more than one way to do it). Â IOW, there's no "one-and-only"
>> design for a r/o USB key. Â In addition to hardware switches, I've also
>> seen multiple-mount scenarios (first mount was r/w, unmount/remount
>> within a small time window was r/o).
>>
>> Bottom line: *anybody* that *ever* claims some method *always* works is
>> confused (never assign to malice what can be explained by ignorance).
>
> If the switch disables the write signal directly then it will be
> impossible to write to the device.  Though there are still three ways
> that I can think of that this method might still allow writing, one is
> hardware failure (broken switch or similar), the second is
> accidentally moving the switch (or maliciously I suppose) and the
> third is Divine Intervention.  Whether this therefore counts as a
> write protection method that *always* works is a matter of
> interpretation.

I can think of a fourth way:
The C-x M-c M-butterfly command in Emacs...