Have you ever wondered how the amount
of flash inside a flash SSD compares to the capacity shown on the invoice?
What
you see isn't always what you get.
There can be huge variations in different
designs as vendors leverage invisible internal capacity to tweak key
performance and
reliability
parameters. ...read the
article
Fast Purge
flash SSDs - when you need more than "Rugged SSDs"
The need for fast data
erase - in which vital parts of a flash SSD are destroyed in seconds - has
always been a requirement in military projects.
That's because if a
disk falls into enemy hands the data protection offered by
encryption is not
safe enough.
Encryption can be defeated in a short period of time by
brute force methods and also by master keys being stolen.
These are
unacceptable risks in war time - which is why various methods of fast purge
have been developed in the past decade - including blowing critical datapaths
using elevated currents (fuse sputtering technology) and destroying parts of a
chip using elevated voltage. This is done by special destructive programming
circuits which are designed into the SSD silicon. The so-called "erase"
which is intrinsic to flash write operations is not a useful mechanism for this
purpose because flash memory cells have
remanence -
which means their previous contents can be read under certain test conditions.
Another new method (unveiled in
2011 and
invented by
Pangaea Media)
appears to use a triggerable ultrasonic transducer integrated in the SSD
casing - which destroys memory chip substrates using energy from an embedded
battery.
Vendors don't like to talk much about the implementation
details for obvious reasons. But the fast purge options offered typically fall
into 2 categories:- fastest operation, or lowest power.
Another fast
erase / purge option available to designers is the option to render the SSD
unusable (destroying key operating parts of the SSD) versus the option to reuse
the SSD in another application.
Although many SSD vendors are offering
their products with extended rugged operating environment capabilities - it's
the availability of fast purge which differentiates "true military"
SSDs which can be deployed in
defense applications.
Many readers have asked for a separate directory of such products to
simplify their search process. Fast purge SSDs are the antithesis of ideal
consumer / enterprise SSDs - because they are designed to defeat
data recovery. The
problem for military SSD designers is that as recovery techniques get better and
raw computing power increases - the demands on the purge systems are increased.
Having
said that - one military SSD company,
RunCore, has inserted
an interesting security feature into a consumer notebook SSD range (launched
Q1 2010) whereby if your notebook is stolen you send a (phone) text message to
it - and it destroys the data.