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IBM To Demo Crusoe Thinkpad
CoreDump writes: "Just ran across this story at News.com about IBM announcing that they will demo a Crusoe based Thinkpad at PC Expo. This is what I've been waiting for, not an "appliance", but an actual full-blown system that can be used every day. They aren't planning products until the fourth quarter, but I know what *I* want to find under the tree on Dec. 25th.
"
The key to lower heat output is lower power consumption. The Crusoe accomplishes this in the following ways:
u soetechwp.pdf
1. By performing scheduling and the like in software, the Crusoe has far fewer transistors (read ~1/4) than a PIII or Athlon. Hence, lower power consumption.
2. In addition, Crusoe has a power management "system" that actually lowers the clock speed whenever less speed is needed. All chips should do that, but they don't. And it doesn't slow down memory access at all, since the bottleneck there is not the processor clock speed. This technology is referred to as LongRun. Here's a quote from Transmeta:
"In a mobile setting, most conventional x86 CPUs regulate their power consumption by rapidly alternating between running the processor at full speed and (in effect) turning the processor off. Different performance levels can be obtained by varying the on/off ratio (the "duty cycle"). However, with this approach, the processor may be shut off just when a time-critical application needs it. This can result in glitches, such as dropped frames during movie playback, that are perceptible (and annoying) to a user.
In contrast, the TM5400 can adjust its power consumption without turning itself off - instead, it can adjust its clock frequency on the fly. It does so extremely quickly, and without requiring an operating system reboot or other slow and involved OS or BIOS operation. As a result, software can continuously monitor the demands on
the processor and dynamically pick just the right clock speed (and hence power consumption) needed to run the application - no more and no less - so no power is wasted. Since the switching happens so quickly, it is not noticeable to the user.
Finally, the Code Morphing software can also adjust the Crusoe processor's voltage on the fly (since at a lower operating frequency, a lower voltage can be used). Because power varies linearly with clock speed and by the square of the voltage, adjusting both can produce cubic reductions in power consumption, whereas conventional CPUs can adjust power only linearly. For example, assume an application program only requires 90 percent of the processor's speed. On a conventional processor, throttling back the processor speed by 10 percent cuts power by 10 percent, whereas under the same conditions, LongRun power management can reduce power by almost 30 percent (0.903 = 0.73) - a noticeable advantage!"
For more information I highly recommend everybody to read "The Technology Behind Crusoe(TM) Processors".
Available at:
http://www.transmeta.com/crusoe/download/pdf/cr
With the same power consumption, and at comparable cost (maybe?), as a P3 laptop, they could make a multiprocessor Crusoe system that blows away anything else out there.
Or we could all go do things that aren't insane, but what fun would that be?
I don't know about Linus, but here's Alan Cox on a Chip.