Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
Power Hardware Technology

ARM Designer Steve Furber On Energy-Efficient Computing 195

ChelleChelle writes "By now, it has become evident that we are facing an energy problem — while our primary sources of energy are running out, the demand for energy is greatly increasing. In the face of this issue, energy-efficient computing has become a hot topic. For those looking for lessons, who better to ask then Steve Furber, the principal designer of the ARM (Acorn RISC Machine), a prime example of a chip that is simple, low power, and low cost. In this interview, conducted by David Brown of Sun's Solaris Engineering Group, Furber shares some of the lessons and tips on energy-efficient computing that he has learned through working on this and subsequent projects."
This discussion has been archived. No new comments can be posted.

ARM Designer Steve Furber On Energy-Efficient Computing

Comments Filter:
  • by Anonymous Coward on Thursday February 25, 2010 @05:43PM (#31278176)

    That means a portable computer with an ARM processor and a reflective monochrome display big enough to hold normal text pages. In other words an Amazon Kindle DX (separate wired or bluetooth keyboard is fine), but with an open OS that lets me write and run my own programs without having to jailbreak past some DRM crap. Somebody please make something like that? Please??

  • No always has been (Score:4, Insightful)

    by Darkness404 ( 1287218 ) on Thursday February 25, 2010 @05:51PM (#31278316)

    In the face of this issue energy-efficient computing has become a hot topic

    No. That has, and never was the case. The problem is A) Programs now take a lot more CPU usage (compare CPU usage for the same task in Office 2007 and Office 97) B) CPUs are designed primarily to be faster (needed because of point A) C) Battery technology isn't improving as rapidly as the rest of the components.

    Look at the Poqet PC of the '80s, it had very aggressive power management which wouldn't work today. Computers have -always- tried to be energy-efficient in the portable sector. And quite honestly, its about the only sector that needs work on energy-efficiency to gain any benefit.

  • by Lunix Nutcase ( 1092239 ) on Thursday February 25, 2010 @05:51PM (#31278318)

    We just need to see Windows support for ARM, and then we'll be well on our way towards it being a widely available option.

    And you also mean the porting of thousands and thousands of x86 apps as well? If the ARM version of Windows can't run the apps people want, they aren't going to by an ARM netbook.

  • by fuzzyfuzzyfungus ( 1223518 ) on Thursday February 25, 2010 @05:59PM (#31278434) Journal
    http://openinkpot.org/wiki/Hardware [openinkpot.org]

    There are a bunch of cheap 'n cheerful Kindle clones that are supported by the openinkpot firmware, if e-ink is your style.

    If you need the refresh rates of an LCD, I think you may have a problem. There is the OpenMoko Wikireader [wikipedia.org] which is super low power and pretty cheap; but the screen(although touch sensitive) is a little smaller than what you want and the CPU is more of a microcontroller [epson.jp] than what you probably want.

    You might also consider going the OLPC route. That gets you a rather nice monochrome screen(with backlight color optional) and, while x86, it is a ~1watt embedded Geode, not too power hungry. That one is also by far the most "normal computer" like of the bunch(i.e. no having to code around super slow refresh rates, and running basically standard linux, rather than building binaries for some microcontroller).

    Nothing exactly like what you want(that I know of); but there are some approaches...
  • by Darkness404 ( 1287218 ) on Thursday February 25, 2010 @06:00PM (#31278462)
    Because there is almost no market for it. Lets see here

    A) Monochrome displays (other than E-ink) are generally considered to be low-tech, cheap, pieces of junk. Look at how well monochrome TVs are selling... Yes, it does ease strain on eyes and increase readability, but has the other side of making most of... well anything unpleasant to look at other than text.

    B) It will be expensive. Amazon can afford to produce the Kindle at-cost or even with a bit of a loss because they will gain sales in e-books and such. Even if they sell it at a profit they still can buy parts in bulk and make them cheaper than a product with a run of only ~1,000 units or less.

    C) There aren't enough apps. What apps would make sense to port to this device? Lynx? Most other things would need more CPU power (making it non-energy efficient) or a colour screen.

    Really, other than you, this wouldn't appeal to a large enough audience of people. Best thing to do would be to jailbreak an existing e-reader, its simply a bad business decision to make a product with almost no market.
  • by Lennie ( 16154 ) on Thursday February 25, 2010 @06:03PM (#31278512)
    "Finding a computer that will last a year or more without rebooting is hard."

    Really ?

    In our serverroom we have a few which don't get as many security updates (internal systems), they are doing fine, thank you.
  • by NotSoHeavyD3 ( 1400425 ) on Thursday February 25, 2010 @06:05PM (#31278542)
    efficient. I mean if you consider any unit of computation vs energy expended. I bet my current desktop computer would compare from a computation point of view to a super computer from the late 80's. (GFLOP to GFLOP) However my current computer pulls about 300W, I'm pretty sure that's alot better than any super computer from the 80's that would compare to it.
  • Indeed (Score:3, Insightful)

    by Colin Smith ( 2679 ) on Thursday February 25, 2010 @06:07PM (#31278562)

    The phone market has always been looking for ways of extending battery life. I have a phone which is basically a computer with an antenna. It plays videos, music has wordprocessor, gps, maps etc and the battery still lasts up to 3 days.


  • by mirix ( 1649853 ) on Thursday February 25, 2010 @06:42PM (#31279052)

    Bit shift instead of multiply by powers of two

    I'd think a decent compiler should do that automagically, no?

  • by dfsmith ( 960400 ) on Thursday February 25, 2010 @06:50PM (#31279142) Homepage Journal

    Use floats where doubles aren't necessary

    That assumes that floats are more energy efficient than doubles. Not necessarily true on architectures that have hardware floating point and save energy by omitting the float portion. They convert the float to double, do the math, then convert back. Check your architecture!

    On my Intel Core 2, the execution speed is different by about 0.06% between float and double (edge to double). Can't speak to power consumption though. On my Intel Atom 230, the floats are faster by 0.4%. That's almost certainly saving power, but not a lot.

  • Re:Bull... (Score:3, Insightful)

    by maeka ( 518272 ) on Thursday February 25, 2010 @07:04PM (#31279284) Journal

    5:1 - 3:1 is still a net profit.

    Only if you're assuming energy cost is the primary cost.

  • Re:RISC = Good (Score:2, Insightful)

    by emt377 ( 610337 ) on Thursday February 25, 2010 @07:30PM (#31279502)

    i like MIPS... in college, we had one semester of hands on lab work learning everything about a specific MIPS implementation, then another semester writing a compiler capable of compiling itself for the architecture.

    once you can grasp the simplicity and understand exactly whats going on in the chip, features like HyperThreading seem almost stupid because of how much complexity and exceptions they add to the system.

    Of course modern MIPS processors are threaded as well...

  • by Dog-Cow ( 21281 ) on Thursday February 25, 2010 @07:40PM (#31279570)

    You haven't actually ported any non-trivial app, have you?

  • by DarkOx ( 621550 ) on Thursday February 25, 2010 @08:02PM (#31279784) Journal

    I not so sure, it was not all that long ago most of us who even had a computer were working on an 80x86 or 80x88 with a 512k of memory, connected to a 80x25 character monocrome display, with no network interface, and primary storage consisting of a box next to the unit filled with 360k floppy disks.

    You know what we were like pigs in s**t happy too. I have cell phone, not a facy smart phone. I just use it I don't think about it. I charge it Sunday night before I go to bed and I talk and text on it as much as I want to all week long. The batter never goes flat over that time frame.

    I had a smart phone for a little while. It could not even stand by all day. I had to go back because I was afraid I might miss SMS alerts from critial systems because the things battery went flat.

    I would be very happy with a device that was inexpensive enough to leave on the back seat of my car for weeks on end that would be just there if I needed it and ready to go. Something that could connect to the internet wireless-ly and run lynx and those kinda of apps would be just perfect, even if the screen refresh was slow an e-ink based. Things like e-mail would be very doable as well. We don't live in the same world that 80x86 lived in. There is all kind of infrastructure around, let the POP or IMAP server do the thinking, just add a command like TXTPLZ to the protocols that would instruct the server to render messages sent in other formats out as plain characters. Get send html no problem
      becomes 13 and 10. Hell use libcacca to render images as ascii art.

    The software you need to write and run on the device could do allot by simply offloading the thinking to the oh lord dare I say it? cloud...

  • by Sycraft-fu ( 314770 ) on Thursday February 25, 2010 @08:47PM (#31280154)

    Aka lying.

    While it is true that according to best estimates oil is going to become rather scarce in the not too distant future, oil isn't a major provider of power. It is used for power generation, but not near as much as others. Coal and nuclear are the heavy hitters in power generation and both are still extremely abundant. So while we need to consider what will fuel our cars, we are not approaching a situation where the lights go out.

    He's just trying to jump on the green bandwagon to hype up his product. ARM has made a name for themselves providing low power chips. That's why they are so popular with cell phones and the like. He's just playing on that and the big carbon hype going on to try and promote his products.

    As a practical matter, while we do want to find ways to be more efficient always, we still want to use energy. Energy consumption allows for the things that make modern life so much better, allow us to live longer, healthier, etc. What we really want to do is increase efficiency AND find ways to generate even more power in a sustainable manner, be it fusion, solar, geothermal, etc.

  • Windows 95 is way, way worse than any modern OS, even Vista and Windows 7. Back in the '95 days OSes didn't put the CPU into idle mode and certainly didn't support any power management, effectively running the CPU at full throttle 100% of the time.

    Sorry, you made the erroneous assumption that low system requirements equals low power. Try again.

  • by pedestrian crossing ( 802349 ) on Friday February 26, 2010 @04:16AM (#31282516) Homepage Journal

    People put too much stock in the home energy savings angle.

    I hooked up a Kill-A-Watt to my whole computer/media center stack (computer/monitor/stereo/mixer/external HDDs/assorted electronics), and it was pulling about 65 watts. The only thing that pushed that number up was cranking the stereo.

    It costs about 5 bucks a month to leave this stack running 24/7. 5 bucks. If I was to be looking for significant energy savings, I think I would be looking somewhere else.

    Want to save energy? Insulate your house. Take shorter showers.

    Want to save money? Stop drinking cappuccinos and eating fast food, but leave the fscking computer alone.

    anyone who has hooked up a Kill-A-Watt to their computer, and then calculated how much money per year they're spending on it, disagrees with you.

    I've done it and I disagree with -you-.

Never worry about theory as long as the machinery does what it's supposed to do. -- R. A. Heinlein