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I'm running Kubuntu 12.04 on 32 bit and the updater offers a security update 'Linux kernel headers' and 'Linux kernel image for version 64 bit x86 SMP'. Should I install this? And if not, why do I get the offer?

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Check whether your OS is with PAE extension.

A 32-bit computer has a word size of 32 bits, this limits the memory theoretically to 4GB. This barrier has been extended through the use of 'Physical Address Extension' (or PAE) which increases the limit to 64GB although the memory access above 4GB will be slightly slower.

Most dekstop/laptop processor made in past 10 year support PAE.

Since Ubuntu 10.04 and newer support PAE out of the box so it can access 64 address line.In 12.04 its default.

Probably that's why you got that kernel image. 64bit means its capable of 64bit address handling, the kernel image architecture is x86 which points that it is for 32bit system.

Unless you have modified your kernel or using the kernel for system software development,its safe to install kernels provide via update-manager.

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Hello Web-E, thank you very much for your quick and useful answer! But there's still one question left: How can I check wether my OS supports PAE? Or is it so that when I'm running 12.04, which has it by default, if I understand you right, I can be sure that PAE is supported? – Axel Ludwig May 22 '12 at 19:37
Yes in 12.04 its default. Previously PAE was indicated in kernel name, run uname -a. But some user report that in 12.04 it is no longer shown. See here -… – Web-E May 23 '12 at 4:04
Updated - still there! Thanx! – Axel Ludwig May 23 '12 at 10:18

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