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Implementing WP:PIQA (Task 26)
 
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== PAE Xeon only ==


It should be made clear the only IA-32 processor which supported Physical Address Extension as defined by Intel was Xeon. PAE requires BOTH 36 address registers AND 36bit data bus for RAM.
== "offset within page" does not come from the page-table entry ==

The phrase [Combined with 12 bits of "offset within page" from the page table entry...] should surely be [Combined with 12 bits of "offset within page" from the linear virtual address...]. <!-- Template:Unsigned IP --><small class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/83.218.4.174|83.218.4.174]] ([[User talk:83.218.4.174#top|talk]]) 23:56, 12 October 2016 (UTC)</small> <!--Autosigned by SineBot-->

: You are of course correct - and nice catch, that's been on the page for a long time. You can of course make the change yourself if you want. Be [[WP:BOLD]] ! [[User:Jeh|Jeh]] ([[User talk:Jeh|talk]]) 03:08, 13 October 2016 (UTC)

{{Done}}

== As to the PAE kernel for Linux ==

That is a long and old news that even though the processors, x86 or IA-32, lack support of PAE, could also be equipped with PAE kernel. As to the further information, one could retrieve such information from Linux kernel source, from http://www.kernel.org. <!-- Template:Unsigned IP --><small class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/119.53.112.209|119.53.112.209]] ([[User talk:119.53.112.209#top|talk]]) 00:42, 9 May 2017 (UTC)</small> <!--Autosigned by SineBot-->

:The only kernels that can run on a processor without PAE support are 1) kernels without PAE support and 2) kernels that check whether the hardware supports PAE, enables it if and only if present, ''and'', depending on whether PAE is enabled or not, use different code to manage page table entries.

:If you look at the Linux kernel source, in {{mono|arch/x86/include/asm/pgtable_32_types.h}}, you'll see a comment

/*
* The Linux x86 paging architecture is 'compile-time dual-mode', it
* implements both the traditional 2-level x86 page tables and the
* newer 3-level PAE-mode page tables.
*/

:and, in fact, whether the kernel uses pre-PAE or PAE page tables on 32-bit x86 processors is set at compile time, ''not'' determined at run time, so a kernel with PAE support will work only on a machine that supports PAE; a kernel without PAE support will work on a machine that supports PAE, but it won't use PAE and will only handle 4GB of physical memory.


All IA-32 processors had at most a 32bit data bus. 36 address registers only allows paging - it is not PAE support.
:So, no, you can't run a PAE kernel on a processor that lacks PAE support; anybody who believes that it does either hasn't read the Linux kernel source or read it but didn't understand it. [[User:Guy Harris|Guy Harris]] ([[User talk:Guy Harris|talk]]) 03:34, 9 May 2017 (UTC)


Only Xeon had 36bits for RAM. Xeon supported 8GB RAM total. The 8GB was split into 2x 4GB memory banks accessed one bank at a time. The 32bit + 4bit bus allowed a segment selector.
:: yeah, you are definitely correct! <!-- Template:Unsigned IP --><small class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/119.53.116.164|119.53.116.164]] ([[User talk:119.53.116.164#top|talk]]) 12:50, 9 May 2017 (UTC)</small> <!--Autosigned by SineBot-->
(Xeon was technically a 36bit CPU).


⚫
[[User:Onzite.|Onzite.]] ([[User talk:Onzite.|talk]]) 23:25, 10 May 2020 (UTC)
{{Done}}


:No, as that's rubbish. Where's the definition of that per Intel? The article currently has it right [[Physical Address Extension#Hardware support]] - the chipset and motherboard etc have to also support 36 bit, which I know myself certainly some non-Xeons did. <span class="vcard"><span class="fn">[[User:Widefox|Widefox]]</span>; [[User talk:Widefox|talk]]</span> 22:09, 1 September 2020 (UTC)
== 32 bit Windows specific ==


== First Linux kernel to support PAE ==
If the Microsoft Windows discussed is specific to 32 bit, then it would be more clearer to put them in the header.


The section says 2.3.23 but under the old scheme odd numbers were development kernels (2.2 series was the release, 2.3 was concurrent and the development space for what would ship as 2.4). Would probably make sense to also mention which kernel was the first to ship with PAE, since no released distro would use a development kernel. --[[Special:Contributions/97.115.191.42|97.115.191.42]] ([[User talk:97.115.191.42|talk]]) 03:44, 1 May 2022 (UTC)
⚫
[[User:Tsenapathy|Tsenapathy]] ([[User talk:Tsenapathy|talk]]) 17:40, 29 November 2018 (UTC)
As many people who reads the page for quick reference may miss this detail. <!-- Template:Unsigned --><small class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Tsenapathy|Tsenapathy]] ([[User talk:Tsenapathy#top|talk]] • [[Special:Contributions/Tsenapathy|contribs]]) 17:38, 29 November 2018 (UTC)</small> <!--Autosigned by SineBot-->

Latest revision as of 16:39, 16 February 2024


Archives (Index)

This page is archived by ClueBot III.

PAE Xeon only

[edit]

It should be made clear the only IA-32 processor which supported Physical Address Extension as defined by Intel was Xeon. PAE requires BOTH 36 address registers AND 36bit data bus for RAM.

All IA-32 processors had at most a 32bit data bus. 36 address registers only allows paging - it is not PAE support.

Only Xeon had 36bits for RAM. Xeon supported 8GB RAM total. The 8GB was split into 2x 4GB memory banks accessed one bank at a time. The 32bit + 4bit bus allowed a segment selector. (Xeon was technically a 36bit CPU).

Onzite. (talk) 23:25, 10 May 2020 (UTC)[reply]

No, as that's rubbish. Where's the definition of that per Intel? The article currently has it right Physical Address Extension#Hardware support - the chipset and motherboard etc have to also support 36 bit, which I know myself certainly some non-Xeons did. Widefox; talk 22:09, 1 September 2020 (UTC)[reply]

First Linux kernel to support PAE

[edit]

The section says 2.3.23 but under the old scheme odd numbers were development kernels (2.2 series was the release, 2.3 was concurrent and the development space for what would ship as 2.4). Would probably make sense to also mention which kernel was the first to ship with PAE, since no released distro would use a development kernel. --97.115.191.42 (talk) 03:44, 1 May 2022 (UTC)[reply]

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