rasbeer
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Raspbian vs RasPiDebian “squeeze”

Sat May 26, 2012 12:41 pm

What's the difference? I had a look at http://www.raspbian.org/RaspbianFAQ & I'm none the wiser...

(Apologies if this is a stupid question...)

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grumpyoldgit
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Re: Raspbian vs RasPiDebian “squeeze”

Sat May 26, 2012 12:49 pm

I have installed both.
With Debian you get quite a selection of utilities and applications.
With Raspbian you get nothing, absolutely nothing. When you run startx the menus are empty. Not even Midori or Leafpad, or even unzip for that matter. You are expected to decide for yourself what you want to install.

plugwash
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Re: Raspbian vs RasPiDebian “squeeze”

Sat May 26, 2012 12:52 pm

The main difference is the official debian images use software floating point and the "EABI baseline" C abi (which passes floating point values in integer registers). Raspbian uses hardware floating point and the "EABI vfp hardfloat" C abi (which passess floating point values in vfp registers).

The other major differences you should be aware of is that raspbian is based on wheezy while the official images are based on squeeze and since we are having to rebuild everything we are still missing some packages (we are getting closer and closer all the time though).

Finally as grumpyoldgit says the raspbian images hexxeh has been building are far more minimal than the debian images the foundation have been building.

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hexelpdkk
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Re: Raspbian vs RasPiDebian “squeeze”

Sat May 26, 2012 1:01 pm

The official debian image is compiled using settings suitable for the raspberry pi, but does not make full use of the processor capabilities. In particular, floating point operations on the pi processor can use the "Hard Float" mechanism, which is faster, but the official debian image is compiled using "Soft Float" allowing it to be compatible with earlier processor generations.

Debian also have a "Hard Float" port, but this is compiled for the next generation of arm, so will not work on the pi.

Raspbian takes the source from the Debian armhf port, and recompiles everything so it will work on the pi. This should give the best performance for the pi.

The port is still in progress - there are around 35,000 packages in debian, and raspbian still has about 2000 to go. Having said that, I haven't run into anything missing since midori and iceweasel started working.

Edit:
And I'm obviously the slowest typist of the people to respond so far.

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mpthompson
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Re: Raspbian vs RasPiDebian “squeeze”

Sat May 26, 2012 9:43 pm

grumpyoldgit wrote:With Raspbian you get nothing, absolutely nothing. When you run startx the menus are empty. Not even Midori or Leafpad, or even unzip for that matter. You are expected to decide for yourself what you want to install.
Keep in mind that Raspbian is still under development and we've been busy just trying to get all the packages built. We're just starting the process of ironing out the kinks and smooth out the rough edges.

At this time, I would suggest that the Raspberry Pi Debian is best for people who want a working Linux Distribution and explore the Raspberry Pi. Raspbian at this time is really for those who either have immediate need for fast floating point operations or are willing to work with it in its unfinished state to move it forward to a more polished state.

rasbeer
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Re: Raspbian vs RasPiDebian “squeeze”

Sun May 27, 2012 7:23 am

Thanks - that's cleared things up! Perhaps the info above could be used to beef up the Raspbian FAQ & make it a bit more newbie-friendly?

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mpthompson
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Re: Raspbian vs RasPiDebian “squeeze”

Sun May 27, 2012 4:12 pm

Very good suggestion. I updated the FAQ to lead with such a description:

http://www.raspbian.org/RaspbianFAQ

Let me know if that makes it a little clear to new users what they might expect right now with Raspbian. Hopefully, over a short time, we'll adjust the description until Raspbian does reach the point it's suitable to new users.

rasbeer
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Re: Raspbian vs RasPiDebian “squeeze”

Sun May 27, 2012 7:41 pm

mpthompson wrote:Let me know if that makes it a little clear to new users what they might expect right now with Raspbian.
It's a bit clearer, but the motivation for going to all this trouble doesn't really jump out at the reader, and I had to reread things several times to get straight (I hope) the differences between Raspbian, Wheezy armhf & the Debian distro available from ./downloads.

So I tried editing the "What is Raspbian?" section to make everything really explicit:
Raspbian is an unofficial port of Debian Wheezy armhf with compilation settings adjusted to produce optimized "hard float" code that will run on the Raspberry Pi. This should provide significantly faster performance for applications that make heavy use of floating point arithmetic operations (eg?).

The port is necessary because the official Debian Wheezy armhf release is compatible only with versions of the ARM architecture later than the one used on the Pi (ARMv7-A CPUs and higher, vs the Pi's ARMv6).

The official Debian image (available for download from raspberrypi.org) used "soft float" settings for easier compatibility with the Pi. This was necessary due to time constraints (?), but implies that it does not use of the Pi's processor's floating point hardware - reducing the Pi's performance during floating point intensive applications .
(If this seems overlong or is an excessive mangling of reality, please feel to ignore it!)

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mpthompson
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Re: Raspbian vs RasPiDebian “squeeze”

Sun May 27, 2012 8:16 pm

rasbeer wrote:(If this seems overlong or is an excessive mangling of reality, please feel to ignore it!)
Thanks. I updated the FAQ with your text, but slightly altered to reflect what I think the reality is behind why Debian armel was chosen. If you create a login on the Wiki, let me know what your account name is and I'll set it so you can edit the Wiki contents as you see fit. I have the wiki locked up a bit just to chase of spammers who take advantage of fully open wikis.

Thank you for helping to improve the communication as to what Raspbian is and why someone might choose it.

UnaClocker
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Re: Raspbian vs RasPiDebian “squeeze”

Sun May 27, 2012 10:52 pm

There's a pretty simplistic benchmark program called "hardinfo" (apt-get install hardinfo), best to run it in X (just type hardinfo in terminal). Compare the two FPU benchmark scores between the soft float (official) Debian, and the hard float Raspbian, it's dramatic. In one of the two tests, the performance doubled (half the time required to run the test), the other FPU test is SEVEN TIMES faster now. The rest of the tests remained the same, so you're not losing any performance on anything else, only gaining an FPU..

rasbeer
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Re: Raspbian vs RasPiDebian “squeeze”

Mon May 28, 2012 6:44 am

mpthompson wrote:Thanks. I updated the FAQ with your text, but slightly altered to reflect what I think the reality is behind why Debian armel was chosen.
Great - that addresses all the things I was having trouble understanding.

Maybe UnaClocker's benchmark info could be incorporated in the "How fast will Raspbian be?" section?

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