Why the pae kernel

**kansasnoob** · February 3rd, 2012

Update: Please read this:

http://www.phoronix.com/scan.php?pag...tem&px=MTAyNzM

The Ubuntu Technical Board weighed the pros and cons of non-PAE support and came to a decision. The board has decided they will support the non-PAE kernel option until the Ubuntu 12.10 release, so there will still be support in Ubuntu 12.04 LTS. The default i386 kernel in Ubuntu 12.04 LTS will become the PAE-enabled kernel, but the non-PAE flavor will be available.

Below are the details in full from the non-PAE discussion.

Non-PAE kernel disposition
* Kernel team would like to drop non-PAE kernel soon
* TB members generally feel that (1) dropping the current default kernel is too much of a step, and (2) there is still a significant number of users which have non-PAE systems, based on Launchpad bug report data and an ubuntu-devel@ strawpoll
* Maintaining the extra flavour is not much extra work, and not comparable to e. g. the -ti-omap4 kernel which is an entirely separate source tree
* We need a way to prevent upgrades for non-PAE systems. Some options were mentioned:
* Add update-manager check to not offer the upgrade if PAE is not available
* Add libc6/linux preinst to abort the upgrade early if PAE is not available; that's not the best failure mode, but will prevent a safety net for users of `apt-get dist-upgrade`
* '''Agreements''':
* Switch precise over to PAE kernel by default on i386; we retain the option to revert if it causes too much fallout (Colin)
* Drop non-PAE flavour in 12.10; this will give non-PAE systems another 5 years of life time, which is considered enough
* Further discuss upgrade strategy/checks

You'll notice that I specifically highlighted "Switch precise over to PAE kernel by default on i386; we retain the option to revert if it causes too much fallout", therefore it is going to be extremely imperative that those with effected hardware file new bug reports!

I have no hardware effected by this change but you can read a brief summary of what my personal goals are regarding this here:

http://ubuntuforums.org/showpost.php...&postcount=100

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I just completed alpha 2 iso-testing and ran into a number of issues, one question I have is why a fresh install uses the "pae" kernel

Fresh install:

Linux lance-desktop 3.2.0-12-generic-pae #21-Ubuntu SMP Tue Jan 31 20:44:35 UTC 2012 i686 i686 i386 GNU/Linux

Upgrade from Oneiric:

Linux lance-desktop 3.2.0-12-generic #21-Ubuntu SMP Tue Jan 31 18:40:37 UTC 2012 i686 i686 i386 GNU/Linux

The hardware involved is:

Intel(R) Atom(TM) CPU 230 @ 1.60GHz
Intel Corporation 82945G/GZ Integrated Graphics Controller (rev 02)

Sorry to be so clueless

**sgage** · February 3rd, 2012

PAE is a gimmick for allowing a 32-bit installation to access more than about 3.2 GB of RAM. If you're installing a 32-bit version, and the installer detects more than 3 GB of RAM (or maybe even if you don't - not sure), it gives you the PAE kernel. The non-PAE kernel is available in the grub menu under "Previous Linux Versions".

**collisionystm** · February 3rd, 2012

Technically 32 bit should be able to handle 4gb of memory.

Regardless PAE is just a hack. Time to upgrade into the current century and get a 64 bit system.

**bmbaker** · February 3rd, 2012

is there a way to convert a 32bit system to 64bit or do you have todo a new install?

**collisionystm** · February 3rd, 2012

Originally Posted by bmbaker

is there a way to convert a 32bit system to 64bit or do you have todo a new install?

New install

**kansasnoob** · February 3rd, 2012

Originally Posted by sgage

PAE is a gimmick for allowing a 32-bit installation to access more than about 3.2 GB of RAM. If you're installing a 32-bit version, and the installer detects more than 3 GB of RAM (or maybe even if you don't - not sure), it gives you the PAE kernel. The non-PAE kernel is available in the grub menu under "Previous Linux Versions".

Thanks, on that Intel box I have only 2GB of RAM. Further more I just checked an old VIA C-7/P4M800 box with only 1GB of RAM that I'd last used for testing Lubuntu, and both the live and alternate installs resulted in the pae kernel.

So I wonder if that's a bug

**kansasnoob** · February 3rd, 2012

Originally Posted by collisionystm

Technically 32 bit should be able to handle 4gb of memory.

Regardless PAE is just a hack. Time to upgrade into the current century and get a 64 bit system.

Care to loan me a couple grand

I can pay you $10 a month.

**collisionystm** · February 3rd, 2012

Originally Posted by kansasnoob

Thanks, on that Intel box I have only 2GB of RAM. Further more I just checked an old VIA C-7/P4M800 box with only 1GB of RAM that I'd last used for testing Lubuntu, and both the live and alternate installs resulted in the pae kernel.

So I wonder if that's a bug

They give you the PAE kernel by default so you have the option to run more memory without having to futz with it.

Running the PAE is not a problem. Running to much RAM on a 32 bit is.

**collisionystm** · February 3rd, 2012

Originally Posted by kansasnoob

Care to loan me a couple grand

I can pay you $10 a month.

lol wish I could.

You can get a nice dell vostro desktop for 300 bucks from dell.

If you want a new laptop may i suggest a vostro 3000 series from dell. They are awesome. You can also finance through dell for the 10 or 12 bucks a month you are looking for lol.

Nice 17" screen.... have it and love it.

http://www.dell.com/us/soho/p/vostro...84,901q5c14135

**kansasnoob** · February 3rd, 2012

Originally Posted by bmbaker

is there a way to convert a 32bit system to 64bit or do you have todo a new install?

For sure you have to do a fresh install, but I just recently bought my first 64bit hardware. But I'm poor so I reused a matched set of RAM / two 1GB sticks = 2GB / and I found overall performance to be better with i386

I know I could upgrade the RAM for under $50.00 but that's a lot of money to me