OT: USB stick with write protect switch?

[Colin Law]

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.  But, as they say in Perl, TIMTOWTDI
> (there's more than one way to do it).  IOW, there's no "one-and-only"
> design for a r/o USB key.  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.

Colin