What do alternate kernels do?

Discussion in 'Droid Bionic Hacks' started by pabtheghost, Nov 30, 2011.

  1. pabtheghost

    pabtheghost Member

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    havent seen anything on this, but id like to know if if/why i should change mine
     
  2. Dave12308

    Dave12308 Silver Member

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    First, let's define "kernel". The kernel, in Android terms, is the core Linux OS that the Android framwork and Dalvik Virtual Machine run on top of (those 2 things are what make Android, Android.) In the case of the stock Bionic, the Linux kernel is v2.6.35.7

    Now, let's talk about "alternate" kernels. There are 2 things that could be considered an "alternate" kernel.

    First is the "custom" kernel, which is not pertinent to the Bionic due to the locked bootloader. These are created by members of the community from source code, which is downloaded from Google's servers. I used to build custom kernels, and worked with P3Droid back in the early days of root and the Droid 1. Basically, I had to install Linux on my PC and set it up for compiling C++ source code. I used VMWare so I didn't have to have a Linux partition. Then, I had to download the Android kernel source. From there, modifications could be made to do such cool things as overclock the CPU, undervolt the CPU, monitor the temperature, tether wirelessly, and the list goes on. Some of this involves direct modification of the C++ source code, other things involve using a configuration editor to toggle options. Once you finish with all of this, you compile it on Linux and copy it to your device. If all goes well, there ya go, custom kernel. But like I said, unfortunately not pertinent to the Bionic unless the bootloader is eventually unlocked.

    Second is the kernel update, which is packaged with carrier OS updates. Generally, when the Android component of the OS is updated, they update the Linux kernel as well. That's what are referred to in threads such as "5.7.893 radio/kernel"; 5.7.893 is the "system version", which is the Motorola-issued version for the entire OS package (kernel, radio, and Android OS). I am not sure what the kernel version of .893 is, but it's likely later than 2.6.35.7 (something like 2.6.35.21, for example). "Radio" refers to the firmware revision of the actual cellular hardware and updates to this are also included in OS updates. Since we're discussing the kernel here, a kernel update within an OS update is like the kernel updates you see running desktop Linux distributions such as Ubuntu. Generally, they are sort of like Windows security updates, where critical issues are fixed.

    Some people swear by some of the new, non-official updates, claiming improved network performance/stability. But this is a function of the radio firmware, and not the kernel. Since there is no way to update the kernel on your Bionic without installing an OS update that might take you off the official update path I would recommend against it currently.
     
  3. BayouFlyFisher

    BayouFlyFisher Rescue Squad
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    It isn't often a question is answered so thoroughly and well.
     
  4. chris44gw

    chris44gw New Member

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    agree
     
  5. ripper2860

    ripper2860 Member

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    Wow!! What an outstanding and informative response. Definitely should be an FAQ entry!!

    Good question, too!
     
  6. Dave12308

    Dave12308 Silver Member

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    Glad I could be helpful! Whenever I see a question like this, I like to give a clear answer. I am on a crusade to end the epidemic of people jumping into phone modding without being well informed *LOL*

    To be completey honest, with the locked bootloader and all even I am a bit nervous when it comes to modding my Bionic. Maybe i'm taking the chicken way out, but I am happy with its stock performance and am tending to shy away from modding it until there is an established way to get back to 100% stock, updatable condition. If I really get the itch to get back into the dev scene, I may just wait until tax time and pick up a Nexus, even if it means paying retail.
     
  7. SEColwell

    SEColwell Member

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    Keeping my bionic stock for noq

    Sent from my DROID BIONIC using DroidForums
     
  8. skruid

    skruid Member

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    Yep a chicken lol jk, Modding is at your own risk

    Sent from my DROID2 GLOBAL using DroidForums
     
  9. lm2

    lm2 Member

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    Does this tool not provide you with ability to get back to stock?
    R3L3AS3DRoot and 43V3R root for the BIONIC v2.1 - xda-developers
     
  10. pabtheghost

    pabtheghost Member

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    awesome, thanks for the response Dave. so since i rooted and installed the liberty ROM, does that mean ive already gone past the point of no return, or is it only irreversible when changing the radio/kernel?
     
  11. aforcefulthrust

    aforcefulthrust New Member

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    Thanks for the breakdown on the kernel!! Explains allot.

    I am also curious about this. Im currently running R3BLURR3D 1.7 on system version 5.5.892 but was thinking of updating to 893 and the latest TH3ORY rom.

    Sent from my DROID BIONIC using DroidForums
     
    #11 aforcefulthrust, Dec 12, 2011
    Last edited: Dec 12, 2011
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