LinuxQuestions.org - Why 2 versions?

- Linux - Newbie (https://www.linuxquestions.org/questions/linux-newbie-8/)

- - Why 2 versions? (https://www.linuxquestions.org/questions/linux-newbie-8/why-2-versions-500857/)

Howdy all. Im brand spanking new to the *nix world, so please be gentle. I installed CentOS 4 on my PC the other day that I also have Windows installed on. No problems so far, I can still access both OS's. I had even configured the boot loader to boot to Windows by default to make life easier for my wife. But then I run the Up2Date OS updater. Now I have 2 different Linux versions I can run, and Windows is no longer the default.

Version 1: CentOS(2.6.9-42.0.3.EL)
Version 2: Centos-4 i386(2.6.9-42.EL)

I boot to either one and they both act the same. Is this normal? Is there a way to change the boot loader back to Windows default? Is there a good newbie site that is searchable to pick up on basics?

They are the same OS but with different kernels. It appears to have updated your ernel and updated the entries on the boot loader. The update system leaves the older ones intact in case there are problems with the new kernel - that way, you can go back and fix them without having to get too esoteric :)

Quote:

Version 1: CentOS(2.6.9-42.0.3.EL)
Version 2: Centos-4 i386(2.6.9-42.EL)

You'll notice the above version is greater. You'll have to edit your bootloader's config to either move Windows entry to the top or, every time you update your kernel (that's why you have two versions: the updated one, and the older one -- updating a kernel won't remove the old one, in case the newer one wouldn't work), edit the bootloader config to make Windows default. It's like this:

- you have configured two bootable systems (number 2 is default):

1) Linux
2) Windows

- then you update your kernel, adding another Linux kernel to the system; now the list is automatically re-created like this:

1) Linux 1
2) Linux 2
3) Windows

..and there, the default option is still 2 but it's not Windows anymore. Solution: Move the Windows section in the bootloader config (/etc/lilo.conf or /boot/grub/menu.lst depending on which on you use) to be the topmost, and set default to be the first entry (number zero I guess). Then updating the kernel, which adds new entry, won't change the default to another choice, since default is zero which is always Windows if it's the topmost. If Windows is the last entry, it's number grows by one every time a new entry is added before it, so the "default" value will be different since it's number won't change along with the wanted section that "goes downwards" every time.

I didn't note what version I was using before the update. So how do I know which one is the updated kernel? Also, is there a way to change my boot loader back as the new kernel wiped out my settings?

Thats because when you upgraded your system, a newer kernel was installed. The older kernel is not routinely uninstalled just in case you have problems with the new one. If the new kernel works fine for you, then all you need to do is uninstall the old kernel by doing,

Code:

$rpm -qa | grep -i kernel

a list of installed kernels will be listed. Pick the version you want to uninstall and do something like

Code:

#rpm -e kernel-version

in this instance you want to keep the one ending in 2.6.9-42.0.3.EL.

As for Windows being default, just edit your /boot/grub/menu.lst or /boot/grub/grub.conf and make Windows the default.

Edit: I had too many tabs opened so didn't realise others had already helped out. Anyway the kernel you need to uninstall is the on ending in 2.6.9-42.EL.

Quote:

Originally Posted by ChrisR(SQL DBA)

Is there a good newbie site that is searchable to pick up on basics?

You are at it!!!
When you updated your system, it obviously installed another kernel--and then offered you a choice. If you don't see any difference between the two, then just stay with one of them and ignore the other.

To get the default back to Windows: Open a terminal and do this:

Code:

su    (gives you root powers)

<root pasword>

cd /boot/grub

ls    (you should see a file named "grub.conf" OR "menu.lst".

Open this with an editor, e.g.:

gedit menu.lst

(find the line that says "default=#"--change # to the number of the entry that you want to be the default (counting from zero). If Windows is the 3rd entry, then it would be "default=2".))
While you are looking at this file, you can also disable entries for things you do not plan to use--like that extra kernel. Just add "#" in front of each relevant line.

This has got to be a new record---4 other replies while I was typing mine. Let's stop for air while OP catches up.....;)

Thanks to all! I'm booked up for the next several hours, so I'll take a crack at all this later.

As someone commented, apparently I found a good source of knowledge here, lots of replies in a short time.

Thanks again!