I am new here, and I am very confuse about kernel.
I know what ROM is, and the benefit of custom ROM. But I am not sure about kernel. What is it exactly? Please give me a simple explanation.
Is the kernel included in rom when I install a custom rom?
So if I compare Android to Windows, then different Rom is different version of OS (Windows) with different "theme" right? So what about the kernel? What will it change my Windows if I install different version of kernel?
The kernel is the operating system layer that is between the hardware and the user interface.
When you install a ROM, you will install, at the minimum, a kernel and a system image. Sometimes there will also be a modem, and other additional elements.
You can also install a kernel by itself, as long as it is compatable with the system image.
To understand what a custom kernel modifies on your phone, go to the development forum, and read the OP for several of the kernel threads. Specifically, read the change log which lists the new features as they are added. That will help you understand.
Related
Hello
I'm new to this...
I was wondering if I can install the SpeedMod Kernel on my SGS2??
Why this Question:
When I rooted my decive with cf-root and odin I have chosen the Kernel with the same "version" my stock kernel had.
Now I'm not sure if I can install any sgs2 kernel (in this case SpeedMod) or if the "version" is important.
I think that all SGS2 Phones should have the same hardware so I sould be able to use any Kernel. Is that right?
What do I have to be aware of, when I choose a new kernel?
Thanks
Ditschi
Yes you can, don't worry about it. Versions don't care much after all.
Thanks a lot thought that. I'll flash he kernel tomorow.
But what im interested in:
When you say the version doesn't matter why are there so many versions of cf-root? Is'nt that a lot of extra work? Why not useing only one kernel?
Cheers
Ditschi
That's for people who want to stay as close as possible to stock.
The developers compile their kernel to work with any Samsung or TouchWiz based rom.
CF Root extracts the kernels from the specific rom, adds in the goodies and presents it to us for use to root the respective rom. So basically what you have is the stock kernel with root added among other things
ah ok...
That makes sense. Thanks a Lot for the help
Hi,
I am new to android phone. I see on the Android development threads, there are multiple version of ROM
My question is what does a ROM consist of?
1. kernel
2. boot loader?
3. Apps comes with phone (e.g. Setting app, Phone app)
4. android framework
5. radio drivers?
6. gps drivers?
and my next question is for different version of ROM what are the differences?
I know some are porting CM9 some are porting vanilla android source.
But are these rom have the same kernel? same radio drivers /gps drivers/etc?
Thank you.
A rom is a tar file, meaning an ancient and common type of Unix/Linux archive.
You can see exactly what is inside one by executing
tar -tf <rom>
You can even do this on your phone if you have a good rom.
test.im.09 said:
Hi,
I am new to android phone. I see on the Android development threads, there are multiple version of ROM
My question is what does a ROM consist of?
1. kernel
2. boot loader?
3. Apps comes with phone (e.g. Setting app, Phone app)
4. android framework
5. radio drivers?
6. gps drivers?
and my next question is for different version of ROM what are the differences?
I know some are porting CM9 some are porting vanilla android source.
But are these rom have the same kernel? same radio drivers /gps drivers/etc?
Thank you.
Click to expand...
Click to collapse
first question the Vibrant roms usually have all you listed except for #2 bootloaders (with a very few exceptions)
Different roms will have different kernels, framework and gps libraries. there are a few radios to pick from.
Most ROMs have all of that, except sometimes the bootloaders. Major differences in the ROMs are the Android version, appearance and customization. Some ROMs have bugs, though, like GPS won't work or it take a while to connect to wifi. You can usually find out about these bugs if you read some of the comments on the ROM page.
Thanks. The shipped ROM must have a working GPS, WiFi , Radio, Camera, Audio, Speaker, right?
But when I follow the 'Vibrant Development' threads for custom ROM, I see some ROM has GPS issue, others have Mute/unmute problem, wifi issue, etc etc.
My question is when creating these custom ROM, why can't one just copy these drivers from shipped ROM and have everything works?
Thanks.
test.im.09 said:
Thanks. The shipped ROM must have a working GPS, WiFi , Radio, Camera, Audio, Speaker, right?
But when I follow the 'Vibrant Development' threads for custom ROM, I see some ROM has GPS issue, others have Mute/unmute problem, wifi issue, etc etc.
My question is when creating these custom ROM, why can't one just copy these drivers from shipped ROM and have everything works?
Thanks.
Click to expand...
Click to collapse
The last shipped Rom for the Vibrant was a long time ago and was a 2.2 froyo rom. Everything will work if you choose a custom rom based on 2.2.
The drivers, libraries for 2.3.x Gingerbread and 4.0.x ICS don't exist for the Vibrant so the devs mix and match libraries from other phones and old 2.2 stuff.
Sometimes it works, other time not. It's incredable we even have a working ICS despite the bugs.
Hi Im trying to educate my self about android os. Correct me if im wrong but what i understand is kernel is to an engine of a car and rom is to body works of the car. In that sense would i be able to use other roms for a certain kernel or does it need to be a specific rom?
It depends on rom "type"...
Some ones provide compiled modules...
Some other ones need modules build from sources...
Generally into the release notes of any roms, there're those things specified...
If not, in the posts of the release...
In Your question, there isn't the firmware (under kernel and rom).
Why?
Cheers,
M.
some kernel works with more than one rom but maybe u will have problem with your operation functions
Hi all,
I want to know if a rom always contains a new kernel and can you change the kernel without changing to another costum rom?
I'm sure most ROMs come with a kernel that is tweaked, at least a little. That doesn't necessarily mean it will support oc/uc. and yes you can flash a kernel, if compatible with you ROM, at your leisure.
there is no spoon.....
Almost all roms come with a kernel of some type, but I feel like I remember seeing a rom a few months ago that didn't come with any kernel, so you had to flash one right after you flashed the rom before booting up (that's what the dev said if I'm remembering right, I didn't flash the rom).
And yes, you can flash any kernel at any time as long as it is compatible with your device/rom.
Well... if the ROM doesn't contain a kernel (that's kind of common) your previous kernel is retained.
This applies specifically to stock-based ROMs
I have made this Q&A thread to talk about the kernel settings. Feel free to post about battery stats, kernel questions and other stuff!
Q: How do I flash a kernel?
A: There are two main (and popular) ways of doing this, via recovery and via odin. Flash a kernel via recovery is like flashing a rom except that you don't have to do any wipes. Whereas flashing via ODIN requires you to flash the .tar file under 'PDA' or 'AP'.
Q: What is the best CPU Governor?
A: It depends what do you mean about 'best', saying 'best' could refer to the battery life, performance, stability, etc. Elaborate your question to a more clear question.
Q: What is the best I/O Scheduler?
A: Same thing as the previously answered question. However, often people talk about the speed, reliability and stability of an I/O Scheduler
Q: My kernel doesn't have the option to change any of these settings, help!
A: You will have to change your kernel in order to change these settings
Q: Why can't my phone allow me to overclock or undervolt?
A: Most likely the kernel you are using doesn't support these functions. Read the kernel OP before flashing!
Q: What does the kernel version in the phone's settings tell me?
A: Like all operating systems, there must be some layer of software the provides all of the drivers for your phone. A newer version of a kernel (Linux for our case) doesn't necessarily mean that the kernel is better, usually it could provide bug fixes but most developers don't bother updating this anyway.
Q: Is there an app to change my kernel settings?
A: If you read the kernel OP, you would have known the compatible apps for your kernel.
Q: Why does my battery drain faster when I flash a new kernel?
A: Kernels aren't developed to drain your battery, this could be caused by an inconsistency in code that may have broke something in the kernel causing battery drain (highly unlikely these days). You will have to go through a few power cycles (drain battery to a low percentage, recharge and repeat).
Q: What is the best kernel for XYZ rom?
A: Rule from XDA, no best ROM or best kernel, etc. Only recommendations can be given by users. Experiment yourself or find reviews on some combinations.
Q: Why should I switch kernels when the stock is good enough?
A: Custom kernels provide extra functionality for your device that could improve performance and battery life. Sometimes installing a custom recovery can bring bug fixes earlier than a rom update (fixes on kernel side like the FPbug). If you think that playing with a custom rom is too technical already, don't use a custom kernel then.
Q: The kernel I am using has an old recovery version, how do I update the recovery?
A: You can update the recovery in many ways such as by updating the kernel, switching kernels, flashing a newer custom recovery like Philz recovery, etc.
Q: What CPU governor and I/O scheduler do you use?
A: Have a look at my hidden signature section
Q: Can I revert to stock kernel once I flash a custom recovery?
A: Usually you can only do this if you reflash the ROM that you were using.
Q: Why does flashing a ROM remove my custom recovery?
A: It is because most custom ROMs come with their own kernels
Q: Why does my screen turn black after the samsung logo after flashing a kernel?
A: You have flashed the wrong version of kernel on your phone. Check the kernel OP before flashing!
Will be updated with more info soon.