Like many other notebooks in the
emerging class of [less than four pound] subnotebooks, the
NEC Versa UltraLite is powered by Transmeta's TM5600 Crusoe processor.
Incidentally the TM5600 is based on the 0.18 micron processes
and contains 128Kb of L1 / 512KB of L2 cache. Average power
consumption is on the order of 2 Watts.
Unlike Intel processors, the Transmeta chips operate
with very low power requirements and produce relatively little heat
so no fans are required. On the UltraLite, the only
cooling necessary for the TM5600 Crusoe chip is a small section of
venting, enabling the processor to be air cooled.
you aren't familiar with the Crusoe processor, what really makes it stick out from
Intel's offerings, and for that matter just about any other processor, is that
it is a software-based chip. The native language that the Crusoe CPU operates
with is called 128-bit VLIW - Very Long Instruction Word. VLIW is something
that bears no resemblance to that of traditional Intel chips, which are also
known as X86 processors.
What enables the Crusoe processor to interact with the
Windows operating system, or for that matter any program that runs under Windows is the Code
Morphing Software layer that surrounds the chip. Code Morphing makes the VLIW Crusoe processor
x86 compatible and consists of two main modules.
The first module is the interpreter, and its task is
to interpret x86 instructions. The Interpreter also filters the
x86 code so that sections which are executed frequently are passed to the
Translator for optimization. CMS recompiles the x86 instructions into its native language and optimizes them
to reduce the overall number of instructions executed.
The Crusoe processor also also contains its own Northbridge, further reducing
power requirements on the system as a whole.
As most of the Crusoe processor's functionality is
implemented via the CMS software layer, less transistors are needed on the
silicon component of the chip. With less transistors, the power requirements by
the CPU are lessened. Additionally, CMS software upgrades can improve overall
system performance in future systems. For instance Transmeta recently upgraded
from CMS 4.1 to CMS 4.2, a change which saw roughly a 20% increase in
performance, while still further decreasing power requirements.
Flash your way to a faster processor -
first launched the Crusoe processor, one of the most tantalizing
features discussed was the ability to upgrade the performance of the processor
by upgrading the software layer, CMS, that surrounds it. As
it currently stands, CMS is not user upgradeable however. Upgrades are implemented by
the manufacturer as they are released, which is about ever six months
upgrades are very similar to flashing a
BIOS we will have to wait and see if Transmeta eventually allows the end user
the capability of upgrading their processor in the field. The downside to a failed BIOS
flashing has always been a dead motherboard, and with a notebook a similar
condition could be quite devastating.
In weighing the finer points of the
flashing process we can see that most, if not all notebooks on the market
are ACPI compliant. Armed with ACPI one would imagine a range of power-related
safeguards could be put in place to prevent any fatal power outages during CMS
flashing. Considering that notebooks come with their own power source, flashing a
chip on a notebook would appear safer than flashing a motherboard's BIOS
(where the computer is at the mercy of power socket). But in an case, an
upgradeable Crusoe isn't quite here.
LongRun Power Management
Power management comes to the
NEC UltraLite thanks to the LongRun system which varies the frequency and
voltage of the processor many times a second (depending on the workload of the
computer at any one instant). Using built-in management tools Long Run can be
tweaked by the user for performance or economy.
This is how LongRun reacted to the NEC UltraLite loading up Adobe
Photoshop. Notice that both the frequency and voltage of the TM5600 were
scaled back at various points during the boot-up process. The two patterns
appear identical at first but if you look closely you can see distinct
The graphing sample time was set to 100ms.
Inside the Long Run Interface the user is able to tweak
and tune the performance of the computer to their liking while the data charts
read back real-time information on the frequency and voltage of the processor.
LongRun adjusts the speed of the processor dynamically and also works in
conjunction with ACPI (Advanced Configuration and Power Interface) so that
if frequency and voltage scaling hits architectural boundaries, the
processor can switch over to ACPI power management policies.