Hi Tim,
I'd also like to make a point regarding your statement that, "the marginal
cost of additional CPU usage is zero unless your CPU meter is pegged."
This might be true if you are running software-based FDE on a desktop
system or on a notebook PC that is using wall power. However, for
notebook PCs that are on BATTERY, additional CPU usage greatly impacts
your on-battery time.
I've experimented with software-based FDE (granted, not BitArmor, but I
can't imagine the results will be much different), and there is a
SIGNIFICANT decrease in the amount of time you can stay on battery when
using software-based FDE compared to using a self-encrypting drive. The
difference is significant even under light workloads where the drive I/O
activity is low.
Best regards,
Darren Lasko
Principal Engineer
Advanced Development Group, Storage Products
Fujitsu Computer Products of America
Dmitry Obukhov <d.obuk...@samsung.com>
Sent by: fde-boun...@www.xml-dev.com
04/27/2009 02:40 PM
Please respond to
fde@www.xml-dev.com
To
fde@www.xml-dev.com
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Subject
Re: [FDE] how FDE is implemented at system layer
Hi Tim,
It is not about "archaic". It is about ratio between storage throughput
and
CPU computational power. If you use very fast storage (SSD, as I did, or
RAID controller), it can make any CPU relatively "archaic".
"Up to" was received on Dell D630 with SSD (fresh Vista Ultimate) and
intensive read access. On the same machine you can get lower values of CPU
load with lower intensity of storage access. Obviously, CPU load will be 0
if you don't access the data at all. If your results are about 3%, it
means
that your storage is "archaic" relatively to CPU or you do not exercise it
on its full speed.
WBR,
Dmitry
-----Original Message-----
From: fde-boun...@www.xml-dev.com [mailto:fde-boun...@www.xml-dev.com] On
Behalf Of Tim Hollebeek
Sent: Thursday, April 16, 2009 8:19 AM
To: fde@www.xml-dev.com
Subject: Re: [FDE] how FDE is implemented at system layer
> > It is very CPU-consuming
> > process. Up to 48% of the CPU power can be spent on encryption.
>
> Really?
Maybe on archaic hardware. The numbers we've seen are closer to 3%.
And of course, the marginal cost of additional CPU usage is zero unless
your
CPU meter is pegged. "Up to" can be very misleading. Up to 100% of the
information in this email might be wrong. That doesn't mean it is.
Encryption is not a CPU intensive operation on modern machines.
I run our FDE product on my machines, and I often forget it's there.
The overhead is not noticeable.
-Tim
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