Fedora mulls ARM as a primary architecture | Hacker News Reader

Fedora mulls ARM as a primary architecture

lwn.net

33 pointsprotomyth19 comments

What would convince me to use Fedora ARM?

An ARM Laptop with specs approximately on par with a Macbook Pro.

Don't fall for the "race to the bottom" and produce an ARM Netbook w/9-inch screen. That's been done already.

What's the advantage of a ARM-based high-end laptop vs an x86-based high-end laptop?

I'll bite: nothing. In fact, only disadvantages abound. You won't get i5 or i7 like performance at the same value or wattage from an ARM for a few more years.

No fans!? I don't need high-end performance, just good performance with long lasting battery and no heat.

Your entire reply is based on the fallacy that a high-end ARM would operate in the same way a low-end ARM does. Most of the energy and die space, etc. etc. in a CPU is dedicated to the caches. L1, L2, and sometimes L3. And they keep getting bigger even as the rest of the CPU gets smaller.

A low-end ARM doesn't worry about heat because it's "underpowered" (loosely speaking). But if you want to approach the performance of an i5, the natural side effects will be tons of heat, much, much worse battery life, and even then, only mediocre performance.

There's a lot more to a CPU than RISC vs CISC. Intel has put decades of research into chip design and various instruction-level optimizations that take place within the CPU. You're making a big mistake assuming ARM can just directly scale their smartphone/tablet CPUs to the multi-core behemoths that are today's Sandy Bridge and tomorrow's Ivy Bridge. It just doesn't work that way - look at AMD.

At the end of the day and at this point in time, ARM entering the high-performance desktop sector would be as poorly executed as Intel's foray into the low-energy CPU segment with Atom... except it would suck more.

I would love to have an ARM netbook that lasts for a couple of days on a full charge. Actually I'd like one with an e-ink screen. Maybe 13 inches?

What kind of UI would it have? For interactive use (ie: not just reading), an e-ink UI seems hard.

Newer e-ink type screens are better than the older ones about reducing the "flashing" between screen draws (to avoid ghosting) but they still need to do it every once in a while (I believe new Kindle does it every 6 page turns).

It would be purely for reading and typing things. I've got a Kindle, the ghosting is barely visible for me, the flash isn't that much of a bother either.

CPU is rather a small power of total platform power consumption these days. Switching x86 to ARM won't magically get you from 5 to 50 hours of active usage. If you compare MacBook Air and the new iPad, you'll see that the difference is actually rather small:

MacBook Air 11.6 - 35 WHr battery and 5 hours of Wifi Usage at 7 W [1] New iPad - 42.5 WHr battery and 10 hours of Wifi Usage at 4.25 W [2]

e-ink screen may make that last far longer... but if you've spent any time trying to use the e-ink Kindle browser, you'll quickly realize that the lack of fast refresh rate is a very difficult problem to solve in terms of usable UI.

[1] http://www.apple.com/macbookair/specs.html [2] http://www.apple.com/ipad/specs/

Not to mention that the e-ink display would use an irresponsible amount of power should the user choose to, say, watch a video.

As it is a netbook, I assume that the user puts much less demand on a GPU than he would on an Apple device. I was also thinking of using it on the road -- so no wifi.

Since I got my transformer (nominal 16 hours battery) I've stopped using my x86 netbook. In theory I can run more programs on the x86, but having that much battery makes a huge amount of difference (I took it on a train across russia recently), and I've been able to find android programs to accomplish everything I actually want to do with it.

That sounds pretty grand, congrats to you :)

"Primary architecture" in this context just means first class architecture. Both x86 and x86-64 are already primary architectures in Fedora while ARM is currently a secondary architecture.

Are those the only two architectures that Fedora currently considers "primary"?

Yes

This would make the Raspberry Pi distribution a "first class citizen" for Fedora.

Without really absorbing the entire article (it got confusing to me at first glance as to which quote was from a Fedora official representative and which wasn't), I wonder if this is the reason why. Since I believe Fedora is the only officially distributed OS for the RPi, I can imagine Fedora wanting to jump on that chance. There may have been some kind of pressure (even just the request) from the RPi Foundation to make this change.

It makes sense. ARM has a bright future. The difficulty lies in drivers for all the various SoC architectures. I'm not sure how Debian handles that, not having used Debian on ARM.

Having used Debian on an ARM development board, the issue is handled by "you supply the kernel, we'll supply the rest." On most ARM systems there's a robust firmware that allows you to load a kernel from just about anywhere.

For my system, I used multistrap to create a very basic Debian installation. I then TFTP over a kernel and boot using the minimal installation as an NFS rootfs. Once, I got everything to a decent state, all I had to do was copy over the rootfs to a local ubifs flash filesystem and tweak the boot params to boot from the new ubifs root.

Perhaps not, the Raspberry Pi has an old cpu on which armhf distros (like ubuntu) don't work.

I think this is about armhf primary support in fedora.

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