Database Develop

Kernel vs Roms vs Modems

Ive been trying to do alot of reading in learning the past week. i flashed my phone maybe 9 times already atleast. Now i keep reading abouts modem versions then kernels then roms. what are the difference? are they each upgradable on their own? Or do the roms upgrade them by themselves. Thanks in advance.

Some Roms upgrade through rom manager. But most of the time you have to flash the new version to get the update. Don't know much about kernals sorry but may somebody cam clearify for both of us
Sent from my phone exuse the typos(if any)

Put simply, the kernel is the part of the software that talks directly to the hardware, different modifications are included in kernels, such as lagfixes, the ability to overclock, and BLN (backlight notifications). Most of the custom Captivate kernels you see are in fact i9000 kernels that have been tweaked to work on our phones.
Once again put simply, a ROM is the operating system of your phone, it includes applications such as the Launcher, Phone, Contacts, Email, Calculator, Calendar, Market, etc. as well as any custom settings put in by the ROM maker (AKA chef) such as the sideloading of apps and root access. ROMs can be added onto later by the user such as the installation of themes or the removal of bloatware. Most of the recent ROMs are based on i9000 ROMs.
Modems are the software that talk to the cellular radio in your phone, they also seem to effect GPS performance. Modems are bit different from kernels and roms in that there aren't any custom modems. All the modems you see on the forums are from Samsung. Modems from several different Galaxy S variants work on the Captivate.
Most ROMs (and ROM updates) are prepackaged with a kernel and a modem, but all the parts can potentially be upgraded separately with the right knowledge. One thing to keep in mind is that to avoid issues you should not mix your parts. For example, in most cases if you use an i9000 modem with a captivate kernel you will not get any sound on phone calls.
The best thing to do before you flash anything is to read, read, read.

i9000 vs Captivate ROMs

I've done a lot of reading and can't find this exact answer...how can I tell if certain roms are Captivate based or i9000 based? I'm running Cog right now and want to flash and play around with some others, but heard that I should stick to captivate based roms so that i don't have any troubles.
Which roms are which?
Thanks in advance!
Sent from my Captivate with Cognition v3.04 via XDA App

sethjamto said:
I've done a lot of reading and can't find this exact answer...how can I tell if certain roms are Captivate based or i9000 based? I'm running Cog right now and want to flash and play around with some others, but heard that I should stick to captivate based roms so that i don't have any troubles.
Which roms are which?
Thanks in advance!
Sent from my Captivate with Cognition v3.04 via XDA App
Click to expand...
Click to collapse
You are limiting yourself to Cog and Firefly which are the only ones that are Cappy based. Both of those are based off the 2.2 update to the Rogers Cappy.
ROMS based off jpy, js3 are I9000 and you will find that listed somewhere on the rom thread. I've been on I9000 roms for several months now with no issues.
Sent from my phone.

Serendipity 5.5 here, works great! Love it!

So aside from reading about any bugs on the more popular ROMs and choosing my next one based on features and bugs (or lack thereof), I shouldn't have any real issues with any of them? If so, that is what I thought, but just wanted to make sure! At one point, I thought I read that I COULDN'T run an i9000 based ROM.

sethjamto said:
So aside from reading about any bugs on the more popular ROMs and choosing my next one based on features and bugs (or lack thereof), I shouldn't have any real issues with any of them? If so, that is what I thought, but just wanted to make sure! At one point, I thought I read that I COULDN'T run an i9000 based ROM.
Click to expand...
Click to collapse
I9000 roms are based off 2.2.1 froyo and really are better in so many ways than the 2.2 cappy versions. There are some versions that seem to have less issues and that's what I would look for.
Sent from my phone.

Roof King said:
I9000 roms are based off 2.2.1 froyo and really are better in so many ways than the 2.2 cappy versions. There are some versions that seem to have less issues and that's what I would look for.
Sent from my phone.
Click to expand...
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Perfect! Thanks!
Sent from my Captivate with Cognition v3.04 via XDA App

[Q] When to use i9000 ANYTHING on Captivate i897

I bought my Captivate in December, and have since rooted, updated to Froyo through Kies, and even flashed a couple of kernels (currently running Firebird). I log onto and read posts on XDA almost daily, its kind of like my daily newspaper! Anyway, I have never understood how its possible that so many members have an i897 Captivate-based phone, yet is able to run i9000-based modems, kernels and ROMS. I've searched and googled, and can't get a straight answer, maybe my search terms need improvement, I don't know. But, is it possible to have
i9000 ROMS (with a i9000 modem/kernel of course) on our United States i897 Captivate? Or, is it that more members on this forum have i9000 based phones than I thought?

aicirt17 said:
I bought my Captivate in December, and have since rooted, updated to Froyo through Kies, and even flashed a couple of kernels (currently running Firebird). I log onto and read posts on XDA almost daily, its kind of like my daily newspaper! Anyway, I have never understood how its possible that so many members have an i897 Captivate-based phone, yet is able to run i9000-based modems, kernels and ROMS. I've searched and googled, and can't get a straight answer, maybe my search terms need improvement, I don't know. But, is it possible to have
i9000 ROMS (with a i9000 modem/kernel of course) on our United States i897 Captivate? Or, is it that more members on this forum have i9000 based phones than I thought?
Click to expand...
Click to collapse
Im just taking a shot here, but i think its because our roms are based off the i9000 roms... (theyre not the same, but theyre in the same class...)

aicirt17 said:
But, is it possible to have
i9000 ROMS (with a i9000 modem/kernel of course) on our United States i897 Captivate?
Click to expand...
Click to collapse
Yes. If you flash a stock version of an i9000 ROM then you will have orientation and Home button issues though. That is why there are kernels in the Captivate development section that are based on i9000 source code and reoriented along with other tweaks. You should also take care to read and understand exactly what it is that you are doing before attempting to flash any ROM, especially one made for an extremely similar, yet different, phone.

As I've learned the hard way, make sure to stay in the captivate development section. There are plenty of I9000, roms to pick from that will work fine for your i897. Just make sure to either use the kernel with the rom or pick a reoriented one. Keep in mind there is some call quality loss with the i9000 roms. And most of all, be careful with bootloaders.
Sent from my SAMSUNG-SGH-I897 using XDA App

cardassianvol said:
Yes. If you flash a stock version of an i9000 ROM then you will have orientation and Home button issues though. That is why there are kernels in the Captivate development section that are based on i9000 source code and reoriented along with other tweaks. You should also take care to read and understand exactly what it is that you are doing before attempting to flash any ROM, especially one made for an extremely similar, yet different, phone.
Click to expand...
Click to collapse
So, I can take my cappy as it is now (stock Froyo, Firebird kernel), and flash an i9000 ROM, making sure to also flash an i9000 modem and kernel (if the ROM doesn't already come with one), and that's it?

Cdub3 said:
As I've learned the hard way, make sure to stay in the captivate development section. There are plenty of I9000, roms to pick from that will work fine for your i897. Just make sure to either use the kernel with the rom or pick a reoriented one. Keep in mind there is some call quality loss with the i9000 roms. And most of all, be careful with bootloaders.
Sent from my SAMSUNG-SGH-I897 using XDA App
Click to expand...
Click to collapse
Bootloaders, the one thing I haven't read up on yet. Think I'll read, read, read, and then read a little more after that. I forgot about the bootloaders. Thanks for the heads up Cdub3!

aicirt17 said:
Bootloaders, the one thing I haven't read up on yet. Think I'll read, read, read, and then read a little more after that. I forgot about the bootloaders. Thanks for the heads up Cdub3!
Click to expand...
Click to collapse
u only need to get acquainted with bootloaders if you are planning to jump to a gingerbread ROM other than cyanogenmod7 or miui from 2.1/2.2 ROMs. GB bootloader+2.1/2.2 secondary bootloader=

aicirt17 said:
So, I can take my cappy as it is now (stock Froyo, Firebird kernel), and flash an i9000 ROM, making sure to also flash an i9000 modem and kernel (if the ROM doesn't already come with one), and that's it?
Click to expand...
Click to collapse
it must be a REORIENTED kernel in order for it to work. in all honesty, i have found that its better to select any rom from the captivate section rather than using a straight i9000 rom from the i9000 forums. go ahead and try a few out, but you will quickly see why i would suggest getting one of the mature i9000 roms from the captivate section instead. references to front facing camera, lack of haptic feedback on the home key, and other little things will begin to creep up on you. it gets annoying.

aicirt17 said:
So, I can take my cappy as it is now (stock Froyo, Firebird kernel), and flash an i9000 ROM, making sure to also flash an i9000 modem and kernel (if the ROM doesn't already come with one), and that's it?
Click to expand...
Click to collapse
You should flash the i9000 ROM and then flash a reoriented i9000 kernel from the Captivate development section and while the modem must be an i9000 modem when using an i9000 based ROM, you should research which modems support your carrier best. I'll assume you are on AT&T and say you need a modem that supports the 850MHz band if you want 3G support everywhere AT&T offers it when you travel inside the US. The standard i9000 modems support the 1900MHz band, which AT&T uses in my area. I'd suggest following the guides in the Captivate Development section though. Most ROMs there have done this work for you. They are almost all based on the official i9000 releases. There is nothing wrong with playing around after you understand the basics though. I run stock i9000 Gingerbread with the i9000 reoriented kernel by xcaliburinhand. Then I tailor it to my liking.

[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][ROM] Kernels and ROMs

Hello people,
I have a bit of a noob question I guess. It's more about on how the Android (guessing any of it) is structured.
If we take a look into the different threads we find a number of versions of ROMs and stuff. But we also find different versions of Kernels.
My question is for example, if switching from lets say stock Android to a custom ROM( eg. Cyanogenmod, AOSP, etc) will it also change the Kernel or is the Kernel separate. Then again there is the question if any Kernel is compatible with any ROM.
I guess the more appropriate question is, does every ROM come with its own Kernel?
This is more just to have a clearer understanding of how this OS is working. Thanks!