OT: USB stick with write protect switch?

[David N. Lombard]

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.  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.

Just to clarify: I meant that if someone claimed to always be able to 
circumvent a USB stick's write protection, they were confused.  I 
completely agree that there are positive write protection schemes; I 
would be surprised if a switch-based scheme were to fail.

-- 
David N. Lombard
Rossmoor, Orange County, CA

Democracy is two wolves and a lamb voting on what to have for lunch.
Liberty is a well-armed lamb contesting the vote.