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I was reading this. It's about detecting installed kernels. KERNELS???!! Is it possible that I have more than a kernel?? How is that??!!!!!

...so I followed the command in the instructions and this is my output:

username@hostname:~$ dpkg --list | grep linux-image
rc  linux-image-3.11.0-12-generic             3.11.0-12.19                                 i386         Linux kernel image for version 3.11.0 on 32 bit x86 SMP
ii  linux-image-3.11.0-13-generic             3.11.0-13.20                                 i386         Linux kernel image for version 3.11.0 on 32 bit x86 SMP
ii  linux-image-3.11.0-14-generic             3.11.0-14.21                                 i386         Linux kernel image for version 3.11.0 on 32 bit x86 SMP
ii  linux-image-3.11.0-15-generic             3.11.0-15.25                                 i386         Linux kernel image for version 3.11.0 on 32 bit x86 SMP
ii  linux-image-3.11.0-17-generic             3.11.0-17.31                                 i386         Linux kernel image for version 3.11.0 on 32 bit x86 SMP
ii  linux-image-3.11.0-18-generic             3.11.0-18.32                                 i386         Linux kernel image for version 3.11.0 on 32 bit x86 SMP
rc  linux-image-3.8.0-19-generic              3.8.0-19.30                                  i386         Linux kernel image for version 3.8.0 on 32 bit x86 SMP
rc  linux-image-3.8.0-25-generic              3.8.0-25.37                                  i386         Linux kernel image for version 3.8.0 on 32 bit x86 SMP
rc  linux-image-3.8.0-26-generic              3.8.0-26.38                                  i386         Linux kernel image for version 3.8.0 on 32 bit x86 SMP
rc  linux-image-3.8.0-27-generic              3.8.0-27.40                                  i386         Linux kernel image for version 3.8.0 on 32 bit x86 SMP
rc  linux-image-3.8.0-30-generic              3.8.0-30.44                                  i386         Linux kernel image for version 3.8.0 on 32 bit x86 SMP
ii  linux-image-3.8.0-31-generic              3.8.0-31.46                                  i386         Linux kernel image for version 3.8.0 on 32 bit x86 SMP
rc  linux-image-extra-3.11.0-12-generic       3.11.0-12.19                                 i386         Linux kernel extra modules for version 3.11.0 on 32 bit x86 SMP
ii  linux-image-extra-3.11.0-13-generic       3.11.0-13.20                                 i386         Linux kernel extra modules for version 3.11.0 on 32 bit x86 SMP
ii  linux-image-extra-3.11.0-14-generic       3.11.0-14.21                                 i386         Linux kernel extra modules for version 3.11.0 on 32 bit x86 SMP
ii  linux-image-extra-3.11.0-15-generic       3.11.0-15.25                                 i386         Linux kernel extra modules for version 3.11.0 on 32 bit x86 SMP
ii  linux-image-extra-3.11.0-17-generic       3.11.0-17.31                                 i386         Linux kernel extra modules for version 3.11.0 on 32 bit x86 SMP
ii  linux-image-extra-3.11.0-18-generic       3.11.0-18.32                                 i386         Linux kernel extra modules for version 3.11.0 on 32 bit x86 SMP
rc  linux-image-extra-3.8.0-19-generic        3.8.0-19.30                                  i386         Linux kernel image for version 3.8.0 on 32 bit x86 SMP
rc  linux-image-extra-3.8.0-25-generic        3.8.0-25.37                                  i386         Linux kernel image for version 3.8.0 on 32 bit x86 SMP
rc  linux-image-extra-3.8.0-26-generic        3.8.0-26.38                                  i386         Linux kernel image for version 3.8.0 on 32 bit x86 SMP
rc  linux-image-extra-3.8.0-27-generic        3.8.0-27.40                                  i386         Linux kernel image for version 3.8.0 on 32 bit x86 SMP
rc  linux-image-extra-3.8.0-30-generic        3.8.0-30.44                                  i386         Linux kernel image for version 3.8.0 on 32 bit x86 SMP
ii  linux-image-extra-3.8.0-31-generic        3.8.0-31.46                                  i386         Linux kernel image for version 3.8.0 on 32 bit x86 SMP
ii  linux-image-generic                       3.11.0.18.19                                 i386         Generic Linux kernel image
username@hostname:~$

Woah! Hold on a second!! So those things are kernels???!! And I had all that in my system and I didn't know??! I didn't install anything!! Or maybe it's the update manager that did this? ... ... ...If it's true then do I need all this?? If no then it should be taking up lots of space of my drive!! And then how do I clean up??

Please explain as much details as possible! It seems that there's a lot that I don't understand!

842Mono
  • 10,070

2 Answers2

4

The kernel can be updated during a normal update. All the kernels remain on the hard disk and should be able to be booted from the grub menu presented at boot time. I keep the old kernels, there is no harm in doing so.

hatterman
  • 2,330
2

To preface, more information about kernels. At a very high level, the kernel is the actual operating system itself (talks to the hardware, runs applications, etc). You need to have one kernel installed to run Linux.

The kernels that you see listed are installed, but they are not being used (except for the one running). There is no harm in keeping multiple versions, and it's usually a good idea to do so in case you hit any issue with the newer version.

If you don't like them being on your system, they can be removed with:

sudo apt-get autoremove

Which should clear out the unused kernels (along with other unused packages). There's no harm in keeping them, though.

Ross
  • 1,150