Database Develop

Difference between ROM and Kernel?

Hello,
Sorry for this very basic question, I am just wondering what is the difference between a Kernel and a ROM? I see in the development forum there are lots of new Kernels, what are these actually optimizing except underclocking or undervolting (understand that terminology). I am also wondering if the Kernels are specific for the original Nexus One 2.1 Android or can you install for example Modaco or Cyan ROM and then a different random Kernel?
Thanks!

To my understanding, a kernel is what directly interacts with the hardware. Every OS has this, but it's more customizable on our phones since it's based on Linux. The Rom contains the OS itself, and the software and file structure therein. The kernel even can tell the OS how fast the processor goes and how much juice to use from the battery.
Hope that makes sense, as I'm no expert. You can mix and match the two as far as I know. I've mixed them, anyway.

Halorin,
Based on what you said, with my stock vibrant ROM 2.1 JI6 update, it is possible to change the kernel or install another kernel (like the CM kernel)?

tomasitoc said:
Halorin,
Based on what you said, with my stock vibrant ROM 2.1 JI6 update, it is possible to change the kernel or install another kernel (like the CM kernel)?
Click to expand...
Click to collapse
That is really a question better suited to the rom 's development thread, but in general yes you can flash a different kernel. Some kernel/rom combinations work better than others, but you really wont know until you try. Get comfortable with nandroid backups and start trying out different kernel combinations until you find one you like.

Usually most custom roms will include a kernel but they usually have tweaks like coding for 720p, oc, and audio tweaks and what not. Alsways do a nandroid back up and start exploring. When flashing kernels always wipe, I think their are exceptions but its best to wipe just in case. Browse XDA, download a kernel from your phone browser, rom manager install from SD, should be in your downloads folder, backup and wipe, repeat until your phone does what you want.
Sent from my Nexus One using XDA App

which is the better to install???
Thank you your post..
but i can't understand clearly.
so.,
which one is better to install NewRom / Kernal. for android phones.

Neither one is better it just depends on what you want to do.
If you want to totally change over your phone to look and function differently then you need to flash a ROM if you just want to keep the same look but want to enable lets say overclocking then flash an overclocked kernel. If it has to do with the hardware mostly then it's probably something that the kernel can change. Although like mentioned above if you flash a ROM most of the time it will come with a custom kernel.

Dude Random21 said:
Neither one is better it just depends on what you want to do.
If you want to totally change over your phone to look and function differently then you need to flash a ROM if you just want to keep the same look but want to enable lets say overclocking then flash an overclocked kernel. If it has to do with the hardware mostly then it's probably something that the kernel can change. Although like mentioned above if you flash a ROM most of the time it will come with a custom kernel.
Click to expand...
Click to collapse
What he said.
ROMs and kernels are two separate things that have two separate functions. Neither is better than the other, but they do complement each other.

Seshu9899 said:
Thank you your post..
but i can't understand clearly.
so.,
which one is better to install NewRom / Kernal. for android phones.
Click to expand...
Click to collapse
I know both Dude Random21 and codesplice have gone into this, but to try and give a bit more info...
The kernel is kinda like the nervous system of the body. It directly interacts with the hardware (which is how it is able to adjust CPU speed) and it is what allows the ROM to function.
The ROM is the rest of the body. Every other aspect of the phone. In fact, most ROMs include custom kernels. Various ROMs give you various features/enhancements/bugfixes. You will probably notice the biggest change in your phone if you load a custom ROM. Most people load the custom kernels to help with battery life as a lot of them allow you to lower the phones minimum processing speed from 245Mhz to 128MHz.
The ROM can change so many different aspects of how the phone works. There is CyanogenMod which is based off of stock Android with a lot of tweaks, bugfixes, and new features added. There is also MIUI, which is similar to the iOS style (not the same, but much closer than stock Android), and then there are a ton others out there.

Then which Rom is best for my samsung galaxy s???
so i am using froyo.jpjpg on my galaxys.
i want to flash new Rom with upgaraded to gingerbread.
can i flash only rom../ kernal also.
which is best Rom for samsung galaxys.
cynogenmod, miui, .?????
battery drain is very fast now ian running rom/kernal.

Start by going to the forum for your phone.
Sent from my Nexus One using XDA App

thank you...
i Start the post from samsung galaxy s..

Seshu9899 said:
thank you...
i Start the post from samsung galaxy s..
Click to expand...
Click to collapse
your welcomed

Nandbackup + Rom & Kernel
One question: when I do a backup with CWM, it is the Nandroid backup you talk about, correct...? Same thing? So, if I do a backup with CWM, it's a backup only of the ROM, or also the stock Kernel...? Imagine that I do a Rom (GingerDX for example), and flash with a custom Kernel.... If things go bad and I do a restore from my backup (stock) CWM, what do I restore? Rom, or Rom + (stock) Kernel...?

Yes, a backup that is done in ClockworkMod (or Amon_RA) is considered a nandroid backup. And this takes a complete snapshot of your system. Your ROM, your kernel, your apps and your data are all inlcuded. The only thing that isn't included is the fat partition on your sdcard. So if things go bad and you restore your nandroid backup, it will go back to however it was when you made the backup.

thanks a lot. reading this thread clear up a lot of things

Hi!
I am currently running Lite'ning ROM 6.1. XXKH3 Kernel version 2.6.35.11-ninphetamine-2.0.5+ [email protected] #20 on SGSII. Phew.
I've tried a lot of ROMS including MIUI, villain, galmetMIUI ICS version . I like Lite'ning ROM because it gave me the least (virtually Nil) problems (FCs/ reboots) and has almost all the features I need (TV-out that's missing from MIUI, good camera with panorama mode, Recording mode in phone). However I miss the CIFS feature. Is it because the kernel does not support it? Can I get CIFS support if I flash another kernel? Any suggesstions on which Kernel should I flash? I realise that this ROM is pretty old now so Can I get additional features with a newer Kernel.

codesplice said:
What he said.
ROMs and kernels are two separate things that have two separate functions. Neither is better than the other, but they do complement each other.
Click to expand...
Click to collapse
That made everything clear. Thanks man. I'm new to the xda but already flashed a new rom that overclocked my CPU to 1.5 and my HTC Sensation 4G Is running so much better right now. However I wish i knew how to thank people... because i see the thanks meter but cannot find where to thank from.

radoslav.trahanov said:
That made everything clear. Thanks man. I'm new to the xda but already flashed a new rom that overclocked my CPU to 1.5 and my HTC Sensation 4G Is running so much better right now. However I wish i knew how to thank people... because i see the thanks meter but cannot find where to thank from.
Click to expand...
Click to collapse
The rom didn't overclock your phone. The kernel did. READ. You came to the MT4GS forum starting up a storm for people not giving you a direct link to the regular MT4G. How is it you cant find the freakin' "thanks" button? THERE'S A FREAKIN' THANKS BUTTON IN EVERY FREAKIN' POST. OPEN YOUR FREAKIN' EYES.

Sori m jst new here..jst b0ught my f0ne 2 m0nths ago. Flashed r0m: gingercrime ITA, flashed kernel: ver 2.6.35.14 v6. And iv overclock my fone 245-710Mhz, smartass. fone: lg optimus one, running on gingerbread 2.3.3
Many thanx xda developers..!!

[Q] Basic principles for i9000m

so much info here yet can't find some of the simple answers i'm after.
i9000m, bell vibrant, 2.2 Froyo KC1 stock ROM upgraded via Kies.
Rooted, speedmod K13E 500hz kernel flashed via Odin. all good.
so....
i assume there are benefits of moving up the android scales eg 2.2 to 2.2.1 to GB but what exactly are these benefits and are they any better than the tweaks i get from speedmods kernel?
i'm interested in custom roms, but as above, what sort of benefits does one get going from stock to custom roms? (over and above flashing upgraded kernels?) - i read lots of threads about ppl being SOOO happy with their custom rom flashes but not a lot of detail about why they make them so happy!
wondering - should i try to flash GB? should i try another rom? dangers involved with the i9000m?

I like to keep up to date with firmware releases. I'm on 2.3.3 using Darky's 10.1 right now. The main benefit I find in all of this is the customization. Third party ROM's offer a lot more features and user options than stock ROMs.
The dangers...well, doing it wrong could lead you to a bricked phone. But following the guide provided by Darky (or other ROM devs) usually prevent that.

i'm in a pretty similar position to you it seems - have the same specs at present and only down the highway from you!
there are plenty of comparisons out there for the basics - not in xda (lots of great info but def more than basic!) - just google 'froyo vs GB' and it brings up some informative sites comparing the two.
am currently trying to decide on wot rom will be best for me....oh and sorting out the loss of GPS which i've only discovered today - it was there before i flashed speedmod i'm sure!

New to captivate

I just got a captivate last night and i have unlocked and and rooted it
it has a firmware of 2.1 - update 1
idk if thats the most recent update
i was told i can not update the phone with a t-mobile sim card in it so can anyone post a thread on updated versions and what do you all think is the best rom?
THANKS

There is no "best" rom. It's what's "best" for you. Read the forums and learn to flash 2.2 roms first.
I must warn you, flashing becomes very addictive.
Sent from my GT-I9000 using XDA App

Yea i know i have a sidekick 4g and ive tried about every rom on it
thanks for the info though

Tyler0309 said:
Yea i know i have a sidekick 4g and ive tried about every rom on it
thanks for the info though
Click to expand...
Click to collapse
I recommend trying MIUI, the customization is what puts it over the top!
Here are a few different versions of MIUI:
Galnet**What I prefer**
http://www.galnetmiui.co.uk/twooey/v3/Twooey-V3-i897.zip
Prototypes release
http://forum.xda-developers.com/showthread.php?t=1066885
MIUI.us
http://roms.miui.us/1.8.12/MIUI.us_captivatemtd_1.8.12_Eng_Deo_ZipA_Signed.zip

Ok ill give it a try..do i have to update to a different version> im running 2.1 right now

Tyler0309 said:
Ok ill give it a try..do i have to update to a different version> im running 2.1 right now
Click to expand...
Click to collapse
I've not been on 2.1 since phone came out. I would use odin one click to goto 2.2 stock. Root it then install cwm and then follow this guide if your going to try Galnet's MIUI.
http://www.galnetmiui.co.uk/content/forum/guides/(guide)-i897-galaxy-s-captivate-gb-bootloaders/
Then just pop the MIUI.zip on root of sdcard and install from CWM.

Tyler0309 said:
I just got a captivate last night and i have unlocked and and rooted it
it has a firmware of 2.1 - update 1
idk if thats the most recent update
i was told i can not update the phone with a t-mobile sim card in it so can anyone post a thread on updated versions and what do you all think is the best rom?
THANKS
Click to expand...
Click to collapse
Wow... so... You should probably READ a lot more before flashing anything, but I'll give you a few hints to get you going:
1) Make sure you understand what a "PBL", "SBL", "Kernel", and "Modem" are and how they are placed/installed in your phone.
2) Learn how to correctly and safely use ODIN (and/or Heimdall).
3) Learn about the various methods of recovery for "soft bricks", and if necessary for your hardware revision, possibly invest in a jig (also learn what a jig is)
4) There are 2 different types/branches of ROMs for the Captivate:
-- Samsung Branch
-- AOSP Branch
Within the "Samsung" types you have:
- i9000 ROMs (like JVP, JVR, JP8, etc)
- i897 ROMs (like JF6, KF1, etc)
Within the "AOSP" types you have:
- CM7
- MIUI
- Other AOSP-based ROMs
Which is "better" is relative. CM7 and MIUI have features that aren't present in the Samsung ROMs, and both offer a bit more customization than the Samsung ROMs. However, only the Samsung ROMs offer GPU accelerated video playback, and they tend to have significantly better battery life than the AOSP-type ROMs. Also the Samsung-type ROMs used to be much more stable than the AOSP branches, but recently, the tide may have turned in the other direction. Some of the low-level radio settings are also unavailable in any of the AOSP builds. And finally, some of the Samsung stock camera features are unavailable in CM7/MIUI.
It really all depends what you want... Do you want closer to stock "open source" Android? Or do you want Samsung's vision of what they think Android should be?
Also, the whole kernel/modem part is dependent on what branch of ROM you plan on running. When using a i9000-Samsung ROM, you pretty much have to use an i9000 kernel and modem. When using a i897-Samsung ROM, you pretty much have to use an i897 kernel and modem. The rules for CM7/MIUI are a bit more vague, but at the very least you'll need to use a CM7/MIUI (most AOSP-type kernels are interchangeable) compatible kernel.
The best advice is really to try them all out and see what you like the most. If you're currently on stock 2.1 (which it sounds like you are), at the very least you should upgrade to some variant of Gingerbread (2.3.4 preferably). You will definitely notice a big difference in terms of speed and functionality. From there, well, it's all really up to you...
OR alternatively, just start throwing stuff on your phone and see what happens. Just PLEASE don't come crying back in the Captivate General forum with a "OMG I bricked my phone!!! Plz help!!!" thread. Fair warning...

Just a suggestion, but become familiar with Odin one click. Make sure your captivate has 3 button recovery, and read, re- read, and read again the directions of every rom before you flash it. Always make a nandroid back up if possible, and read the threads.if you have questions, so did someone else and the answer is probably already out there .use search. Some People will rip your head off if you don't. as far as miui goes .....i was a flashaholic when I got phone. After switching to miui, It is very unlikely that I will ever leave. Best rom ever imho. And it updates every Friday so that satisfied the flashing urge. Usually it gets better with each release. The last couple have been a little rough though. Might want to spend the 8 bucks and have a download jig on standby. Can get it from mobiltech videos. Its worth it though
Sent from my I897 using XDA Premium App

Shammyh said:
Wow... so... You should probably READ a lot more before flashing anything, but I'll give you a few hints to get you going:
1) Make sure you understand what a "PBL", "SBL", "Kernel", and "Modem" are and how the are placed/installed in your phone.
2) Learn how to correctly and safely use ODIN (and/or Heimdall).
3) Learn about the various methods of recovery for "soft bricks", and if necessary for your hardware revision, possibly invest in a jig (also learn what a jig is)
4) There are 2 different types/branches of ROMs for the Captivate:
-- Samsung Branch
-- AOSP Branch
Within the "Samsung" types you have:
- i9000 ROMs (like JVP, JVR, JP8, etc)
- i897 ROMs (like JF6, KF1, etc)
Within the "AOSP" types you have:
- CM7
- MIUI
- Other AOSP-based ROMs
Which is "better" is relative. CM7 and MIUI have features that aren't present in the Samsung ROMs, and both offer a bit more customization than the Samsung ROMs. However, only the Samsung ROMs offer GPU accelerated video playback, and they tend to have significantly better battery life than the AOSP-type ROMs. Also the Samsung-type ROMs used to be much more stable than the AOSP branches, but recently, the tide may have turned in the other direction. Some of the low-level radio settings are also unavailable in any of the AOSP builds. And finally, some of the Samsung stock camera features are unavailable in CM7/MIUI.
It really all depends what you want... Do you want closer to stock "open source" Android? Or do you want Samsung's vision of what they think Android should be?
Also, the whole kernel/modem part is dependent on what branch of ROM you plan on running. When using a i9000-Samsung ROM, you pretty much have to use an i9000 kernel and modem. When using a i897-Samsung ROM, you pretty much have to use an i897 kernel and modem. The rules for CM7/MIUI are a bit more vague, but at the very least you'll need to use a CM7/MIUI (most AOSP-type kernels are interchangeable) compatible kernel.
The best advice is really to try them all out and see what you like the most. If you're currently on stock 2.1 (which it sounds like you are), at the very least you should upgrade to some variant of Gingerbread (2.3.4 preferably). You will definitely notice a big difference in terms of speed and functionality. From there, well, it's all really up to you...
OR alternatively, just start throwing stuff on your phone and see what happens. Just PLEASE don't come crying back in the Captivate General forum with a "OMG I bricked my phone!!! Plz help!!!" thread. Fair warning...
Click to expand...
Click to collapse
Well said.
Sent from my SAMSUNG-SGH-I897 using XDA Premium App

Tyler0309 said:
I just got a captivate last night and i have unlocked and and rooted it
it has a firmware of 2.1 - update 1
idk if thats the most recent update
i was told i can not update the phone with a t-mobile sim card in it so can anyone post a thread on updated versions and what do you all think is the best rom?
THANKS
Click to expand...
Click to collapse
a very simple and easy way to start with...
2.1 is eclair..
2.2 froyo
2.3 gingerbread..
means 2.1 is oldest and 2.3 is latest in case of official roms..
so obviously new version will hav more features and faster in speed...
so now u can take baby step and install 2.2 ..and use it for few days..and get the feel of it..then again after sometime u can install 2.3...
or else u can directly jump to 2.3....which is gingerbread....u can install stock kf1 on ur phone..its leaked official gb...if u search a bit..u will get it..
then u can use it for a lil while and get the feel of gb stock rom..in the meanwhile u can read xda abt available custom roms..and then install any of them...
coz every memeber here in xda will suggest the custom rom they r using..coz they r lovin the rom then only they r using....like for me..since the time i started flashin..i always used APEX ROM..so i will say its the best....
but again thats just me..
so decision is always urs...

[Q] ROMs and KERNELs

I have a question about kernels and roms regarding the competability. I believed I'm still considered new in the android sector though I have used 2.1, 2.2 and now 2.3.
Over the years, I have been using stock ROMs because and putting in my own kernel to get a good balance of performance and battery life. Recently I've have tried getting into custom ROMs as I felt that some stability issues I have read might be some user experience instead of a real stability issue. So I decided to give a go. I looked at certain ROMs but decided to go with more popular ROMs like DarkyRom, they until then I somehow bricked my phone (not ROM issue) and manage to save it back, I decided to go for a newer ROM, which might be as popular as my previous ROM. I decided to go for Doctorz Rom, since all these custom ROMs usually come with another kernel already, is it perfectly Okay to flash any other kernel (Kernel are competitable with the version of the firmware, of course) on the ROM, irregardless of whether the ROM is customized by a developer or not. Example, DarkyRom comes with darkcore kernel (I flashed it to speedmod because I saw that you can do it), Doctorz Rom come with semaphore kernel.
My question in simpler terms, is whether can I flash Doctorz Rom with say, darkcore or speedmod kernel?

simple question for which I am afraid there is no one, simple answer. Some roms play nice with most, if not all kernels, some don't. Similarly, some kernels seem to work with just about every rom, many do not. Hardcore's kernel is one of the more robust ones and usually works with most roms.
Part of the issue is the scripts used in many roms and kernels and what is left behind when you copy a new program to conflict with the new stuff.
(1) Always read the directions on any new kernel or rom.
(2) A clean phone will decrease the chances of having issues with any newly flashed kernel or rom. If your phone is cleansed correctly, any issues are solely a problem of the newly flashed firmware. Bits of legacy program can and do cause issues, which is why a system clean is important.

Thank you, that was the answer I needed

If you were happy with stock ROMs, you should be looking at slightly tweaked stock ROM. I was using Darky with all its bells and whistles for quite a long time. But recently I started to look for something more closer to stock versions and found Simplicity which does pretty good job for me so far.
The choice of ROMs and kernels is so wide that it's hard to decide and it depends if we want to achieve speed or stability. But you can mix ROMs and kernels definitely. I was using Darky ROM JVR with Semaphore kernel completely fine.

stiwipl said:
If you were happy with stock ROMs, you should be looking at slightly tweaked stock ROM. I was using Darky with all its bells and whistles for quite a long time. But recently I started to look for something more closer to stock versions and found Simplicity which does pretty good job for me so far.
The choice of ROMs and kernels is so wide that it's hard to decide and it depends if we want to achieve speed or stability. But you can mix ROMs and kernels definitely. I was using Darky ROM JVR with Semaphore kernel completely fine.
Click to expand...
Click to collapse
I decided to use custom rom because of the features, since i had nv used one before. I cant deny that stock ROM gives a very neat and clean rom which sometimes leads to more speed/battery life, but lets give these developers some.chance as well
Sent from my GT-I9000 using XDA App

[Q] First-Time Custom ROM&/Kernel, need Answers

Hello
I've spent the last 24 hours browsing the O2x section of XDA, and decided that I might change the ROM and/or kernel. I'm considering either Paranoid Android or DjangoManouche ROMs with the KingOfBirds Kernel (If i go with DM) or Kowalski Kernel. However, I have some questions that I just can't find the yes/no answer for. Would anyone be able to answer these for me?..
1. I am running Stock Rooted ICS V30A with CWM v6.0.1.5, busybox and adb installed, which I assume I achieved through steps 3 and 8 on the AIO toolkit because I didn't do anything else.
Does this translate to "I am on the new partition layout with EXT4, have cwm recovery and can proceed to install kernels and ROMS for the new partition layout"?
2. I generally use my p990 for gaming, movies and internet yet still using it as a phone at school. None of the kernels (Kowalski's or KingOfBirds) I am looking at using state whether or not they have Tegra H/W acceleration support, which I do not want to loose. Do the above/all kernels for the p990 support H/W acceleration? :fingers-crossed:
3. Do the kernels and ROMs above still allow me to edit vold.fstab and have a 32gb internal memory from my sd card?
4. I see a lot of people saying CM10 is the best, but a lot of posts with questions and fixes for bugs with it. Any users of this one able to tell me if it is stable and would be suitable for me (see question 2)?
And if you are using DM or Paranoid Android, what are they like for someone who wants a nice fast stable O2X?
5. Will backing my apps up with Titanium and zipping my internal storage be enough to save my game data? $9m on Hill Climb Racing I don't want to loose.
6. When I am changing, should I format my phone in cwm, and then flash the kernel after ROM? (eg DM -> KingOfBirds)

hi there! i'll try to answer some of your questions:
1) you are on the new bootloader and should flash rom's for this particular setting(this doesn't necessarily mean you can't go back to the old bootloader-search for unbrick tutorial in development section)
2) from what i know they do(someone correct me if i'm wrong)
3)i don't know
4)i can assure you that official cm10 is an excellent rom and you should try it ) (i for one never had any major problems(bug call,bsod) and will return to it after some testing )
5) i think it will do just fine
6)every custom rom has some guiding points in the first post(and second and maybe third ) ) please do follow them and you will have no trouble.
good luck!

vader20 said:
hi there! i'll try to answer some of your questions:
1) you are on the new bootloader and should flash rom's for this particular setting(this doesn't necessarily mean you can't go back to the old bootloader-search for unbrick tutorial in development section)
2) from what i know they do(someone correct me if i'm wrong)
3)i don't know
4)i can assure you that official cm10 is an excellent rom and you should try it ) (i for one never had any major problems(bug call,bsod) and will return to it after some testing )
5) i think it will do just fine
6)every custom rom has some guiding points in the first post(and second and maybe third ) ) please do follow them and you will have no trouble.
good luck!
Click to expand...
Click to collapse
Thanks a million vader I'm going to give CM10 a shot on that note, but like you said if someone can confirm for sure if the H/W acceleration works that would be great too.

I don't think that h/w acceleration is something that lacks in the post-cm9 roms. After lg released both official ics, sources and our cm device maintainer aremcee(ricardo) got hold of them all stock roms and cm variants have hwa. I can confirm that tonyp, in his ParanoidAndroid has the option to assign which app to use hwa

vader20 said:
I don't think that h/w acceleration is something that lacks in the post-cm9 roms. After lg released both official ics, sources and our cm device maintainer aremcee(ricardo) got hold of them all stock roms and cm variants have hwa. I can confirm that tonyp, in his ParanoidAndroid has the option to assign which app to use hwa
Click to expand...
Click to collapse
Cool ok, Thanks again Just one last question - should I install kernels before/after zip if not specified by creator?I think I'm going to try pengus77's kernel and CM10 build for the new bootloader.

Flash the kernel after you're done with the rom. Cheers!

vader20 said:
Flash the kernel after you're done with the rom. Cheers!
Click to expand...
Click to collapse
That was the last question hopefully Backing up my phone atm (done cwm, titanium and AIO backups, i should be covered ) and then I'm going to shoot this rom and kernel at it. I'll post back how it goes.