Debian Derivative Optimized for the Raspbery Pi Released 95
sfcrazy writes "The Raspberry Pi foundation has announced the release of the first SD card image based on the Raspbian distribution. The image will make it easier for Raspberry Pi users to switch from 'generic' Debian Squeeze to this 'optimized' image."
The new image is based on Wheezy and optimized for ARM with floating point instructions, and supersedes the Squeeze based soft float image. Benchmarks show much improvement in performance, and the updated software in Wheezy generally improves the usability of the Raspberry Pi.
Re:Why fork? (Score:5, Informative)
Re:Why fork? (Score:5, Informative)
They haven't changed much code, only recompiled it with different settings, so there isn't anything to push back to Debian.
Re:In related news... (Score:4, Informative)
Before & after. Because broadcom does not subsidize it (they would go broke at the rate it is being produced ~ 4000 per day)
Re:Slashdotted already (Score:5, Informative)
Re:In related news... (Score:4, Informative)
That doesn't mean it's subsidized. Subsidized implies that Broadcom is paying for each Raspberry Pi, either through selling components at a loss or by giving cash to the foundation.
If you mean Broadcom gave the Raspberry Pi Foundation a deal on components that would normally only be available to bigger customers, I can believe that. Actually subsidizing each board? Doubt it.
Re:The Raspberry PI is currently underpowered (Score:4, Informative)
Re:The Raspberry PI is currently underpowered (Score:2, Informative)
Little Attiny board, $5.
Atmega328 board, $12.
Arduino Board, $20.
Current Pi model, $35.
Your solution and others, $72
Tablets, small computers, $200
etc.
Right tool for the right job.
Re:The Raspberry PI is currently underpowered (Score:4, Informative)
It depends on the application. The A15 would be the wrong thing if you were interested in minimizing:
*cost
*design complexity
*power
All of which the Pi is interested in doing.
Re:armhf? (Score:4, Informative)
Debian armhf in testing and unstable has a minimum CPU requirements of ARMv7-A+VFPv3-D16+Thumb2. Unfortunately, the Raspberry Pi CPU doesn't meet these specs.
What Raspbian did was rebuild virtually all Debian Wheezy packages to the ARMv6+VFPv2 specs of the Raspberry Pi. Fortunately, the armhf ABI is fully supported on ARMv6 which means that Raspbian built packages run fine under Debian Wheezy armhf. This made the port much easier than it otherwise might have been as all building occurred on Debian armhf systems and the resulting binaries just needed to be verified free of ARMv7 code.
Re:In related news... (Score:5, Informative)
It was explained way back in the early days how it's being done.
Broadcom originally agreed to keep the fab running when they get a big order and produce a small number of extra chips which they'll sell to the foundation for the bulk price.
Re:Why fork? (Score:5, Informative)
Why not contribute the changes you make back to main line Debian?
Well it's not much of a fork, much more a port.
The debian foundation has two ARM binary versions, the 'performance' version (armhf) that's compiled for ARMv7 or better chips, and the 'compatible' (armel) version that's compiled for IIRC ARMv4 or better.
One of the reasons the pi is so cheap is it uses an older SoC, based on ARMv6. The cortex chipsets A9 you see in say, the iphone or samsung SoC are ARMv7 instruction set based. So up to now, the standard raspberry pi debian distro was the vanilla armel squeeze, with a wheezy armel beta. However, the pi ARMv6 does have floating point hardware that allows for 'hardfloat' compilation rather than the 'softfloat' compilation option - which is used in the ARMv7 version of debian, but not the armel version. Using the hardware support for floating point calculation is obviously faster than doing it in software emulation, thus the new port to take advantage of every little bit of performance you can get out of the $5 SoC on the pi.
So raspbian is basically debian ARM, but all the binary packages have been recompiled with the hardfloat option to take advantage of the floating point hardware; they're using wheezy as the target, which is current debian testing IIRC. It's debian armhf, but compatible with the v6 pi. The Debian Foundation weren't interested in supporting a 3rd version of debian on ARM hardware, which is entirely fair enough - the amount of people interested in an ARMv6 with hardfloat who aren't using the pi is going to be very small, though they can of course run raspbian on their hardware too if they also have ARMv6 with hardware floating point; it's not like debian are rolling in money themselves. They were happy for a 'roll your own' version though, which is what has happened.
Last I checked, the raspbian project team (which is basically two guys) had successfully compiled basically everything in the debian package tree, along with keeping up to date with the constantly changing nature of debian testing; they had a compile farm running continuously to keep up, and the setup is worth reading about when the raspbian site comes back; it's a tiny operation that's giving hundreds of thousands of pi owners a significantly faster default distro on a shoestring budget. I think it's brilliant, and is an excellent example of why open source is so awesome. Want an entire OS and software custom compiled to get every ounce of performance out of the hardware? Go for it! And look, these guys have done it for you!
Re:Why fork? (Score:5, Informative)
From the Raspbian FAQ:
For the great majority of Raspbian users, for practical purposes the answer is "No". Packages from the Debian repositories cannot and should not be used with Raspbian. However, if you really know what you are doing and can deal with a file system that may no longer boot, it may be possible to get certain select Debian packages working with Raspbian. The rest of this answer deals with how that might be done.
Debian armel packages use the soft float ABI which is incompatible with the hard float ABI used by Raspbian. In theory it should be possible to install Debian armel packages in parallel with Raspbian packages using multiarch. However multiarch setups conflict with a hack we had to make to support the videocore libraries and there are other potential issues too. As such we don't currently recommend or support multiarch configurations with Debian armel and Raspbian armhf.
Debian armhf packages should be compatible with raspbian packages but a system with such a mixture WILL NOT RUN ON THE PI. Furthermore there may be corner cases where libraries build slightly differently on Raspbian. Such mixed systems can be useful for development (they were used heavily in the process of creating Raspbian) but are not recommended for general use.
Architecture independent ("arch all") packages are compatible between Debian and Raspbian. Source packages should in general be compatible though some may need modification to adjust compiler settings (most Debian packages just use the compiler defaults but some use their own settings for various reasons).
Re:Why fork? (Score:5, Informative)
Good question, the changes we make in raspbian come into basically three categories.
1: changing compiler defaults. Theese can't be pushed upstream until/unless the debian tools get an understanding of flavours*. This is a subject I intend to bring up on the debian mailing lists in-time but it may well cause a flamewar.
2: hacks, it's inevitable that when you have only two people doing a project on this scale that you will run into issues that you don't have the manpower to solve properly and so have to hack around to keep things moving forward. Such hacks include things like reducing optimisation levels, using non-default gcc versions and disabling testsuites. I don't think debian would want these changes.
3: proper bugfixes, I do try and push these back to debian where possible.
We do not intend to be a fork, the VAST majority of source packages are imported from debian and rebuilt with no source changes whatsoever.
* a flavour is a variant that is binary compatible but has different minimum CPU requirements.
Re:Why fork? (Score:5, Informative)
For the record we are NOT cross-compiling. We are building natively on arm hardware (though admittedly not on Pis)
Re:Why fork? (Score:4, Informative)
You can use official debian armel. It'll just be bit slower.
Re:I guess it depends... (Score:4, Informative)
They can be separated and are in many countries. You were not paid $50 from your phone company. You received a loan from your phone company for the cost of the phone plus the fifty dollars. You will repay the loan over the next few years in the form of inflated rates for your service. If you continue to use the phone on their network beyond your contract terms then you will still be paying the subsidy without getting any benefit.