Windows XP End of Life Approaching

[TELVM]

Re: Windows XP End of Life Approaching

... it still makes sense why a PAE kernel still allows only 3.25 GB/process - that's because even with pae, a process still can't access more that 32 bit address space ...

It's not the max virtual address space per process that is crippled by decree in the PAE kernel, but the maximum amount of physical memory that can be managed by Windows, 'courtesy' of the Kernel-WindowsMaxMemAllowedx86 license value. Click here and scroll down to 'License Values'.

... Fortunately, it does not mean you can't have multiple applications using 3.25 GB ...

And the non artificially limited 32bit Windozes readily profit from that fact:

[mariushm]

Re: Windows XP End of Life Approaching

.. and Windows 2000 datacenter supports 32GB as well.

PAE support was disabled in Windows XP SP2 due to too many incompatibilities in drivers and software. You can enable it but Windows will ignore it.

[TELVM]

Re: Windows XP End of Life Approaching

^ Wrong, PAE support is not disabled at all. As a matter of fact:

... Windows automatically enables PAE if DEP is enabled on a computer that supports hardware-enabled DEP ...

http://msdn.microsoft.com/en-us/libr...=vs.85%29.aspx

It's the max manageable physical memory what is limited by decree, irrespective of if PAE is activated or not.


As for the 'incompatibilities in drivers and software', that's plain nonsensical. Imagine they'd launch Tiles 8.2 x64 crippled to 6.66GB max of physical usable RAM, alleging 'incompatibilities in drivers and software'. Even Forrest Gump may suggest: 'Then you need to fix your drivers and software, you morons'.


PAE was introduced with the Pentium Pro back in the Jurassic times. Windows 2000 and Windows XP up to SP1 were not RAM crippled. As Geoff Chappell puts it:

Note that for nearly 5 years, i.e., from Windows 2000 up to but not including Windows XP SP2, Microsoft did not actually prohibit the use of memory above 4GB by any editions of its current Windows product, whether for servers or clients. Perhaps those incompatible drivers hadn't been noticed yet ...

[Per Hansson]

Re: Windows XP End of Life Approaching

PAE was introduced with the Pentium Pro back in the Jurassic times. Windows 2000 and Windows XP up to SP1 were not RAM crippled. As Geoff Chappell puts it:

Note that for nearly 5 years, i.e., from Windows 2000 up to but not including Windows XP SP2, Microsoft did not actually prohibit the use of memory above 4GB by any editions of its current Windows product, whether for servers or clients. Perhaps those incompatible drivers hadn't been noticed yet ...

Yea but how many gaming systems and workstations existed before 2005 with 4GB of RAM or more?

And is I've said before, PAE is not always easy to enable on a 32-bit OS, even if as you say it's highly illogical that such a system would then be stable with a 64-bit OS.
But that just confirms how lazy programmers are doesn't it?

https://www.badcaps.net/forum/showthread.php?t=23454

[ddscentral]

Re: Windows XP End of Life Approaching

.. and Windows 2000 datacenter supports 32GB as well.

PAE support was disabled in Windows XP SP2 due to too many incompatibilities in drivers and software. You can enable it but Windows will ignore it.

PAE switch in boot.ini does enable XP to address memory above 4GB, but the kernel does not make that memory available to programs.

But you can use memory above 4GB to create RAM disks.

I've discovered this when playing with a RAM bootable XP image.
Without PAE switch, attempting to create a RAM disk using memory above 4GB would BSOD.

[TELVM]

Re: Windows XP End of Life Approaching

PAE switch in boot.ini does enable XP to address memory above 4GB, but the kernel does not make that memory available to programs ...

^ Exactly.

... But you can use memory above 4GB to create RAM disks ...

Or to create RAM caches.

Watch this particular, Microsoft certified , ramdisk software brag about:

... Our patent pending technology can access memory beyond the limitation imposed by a Windows 32-bit operating system! In other words, RamDisk Plus 11 can use "unmanaged" Windows' memory e.g. above 4GB. It can also use the stubbornly inaccessable memory between 3.2GB and 4GB ...

http://www.superspeed.com/desktop/ramdisk.php

Oh the irony!

[mariushm]

Re: Windows XP End of Life Approaching

http://support.microsoft.com/kb/888137

If you are running Windows Vista or if you have upgraded Windows XP to Windows XP Service Pack 2 (SP2) or a later version, the memory that is reported in the System Properties dialog box or by the System Information tool (Msinfo32.exe) has changed. This symptom occurs if the following conditions are true:

The computer has 4 or more gigabytes (GB) of RAM.
The computer is using Physical Address Extension (PAE) mode.

Note PAE mode is enabled by adding the /pae parameter to your Boot.ini file in the root folder of the system drive.

For example, before you upgrade to Windows XP SP2, the System Properties dialog box may report approximately 3.87 GB of RAM. The System Information tool may report that the total physical memory is approximately 3,540.00 megabytes (MB). After you upgrade to Windows XP SP2, the System Properties dialog box may report approximately 3.12 GB of RAM, and the System Information tool may report that the total physical memory is approximately 2,770.00 MB.

This issue occurs because of a design change in Windows XP SP2 that is also included in Windows Vista. The changes were made to PAE mode behavior to improve driver compatibility.

To reduce driver compatibility issues, Windows Vista and Windows XP Service Pack 2 or a later version include hardware abstraction layer (HAL) changes that mimic the 32-bit HAL DMA behavior. The modified HAL grants unlimited map registers when the computer is running in PAE mode. Additionally, the kernel memory manager ignores any physical address that is more than 4 GB. Any system RAM that is more than the 4 GB barrier would be made unaddressable by Windows and be unusable in the system. By limiting the address space to 4 GB, devices with 32-bit DMA bus master capability will not see a transaction with an address that is more than the 4 GB barrier. Because these changes remove the need to double-buffer the transactions, they avoid a class of bugs in some drivers that is related to the correct implementation of double buffering support.

As for the 'incompatibilities in drivers and software', that's plain nonsensical. Imagine they'd launch Tiles 8.2 x64 crippled to 6.66GB max of physical usable RAM, alleging 'incompatibilities in drivers and software'. Even Forrest Gump may suggest: 'Then you need to fix your drivers and software, you morons'.

Tell that to my Leadtek Winfast 2000 XP Expert TV tuner, which used to shit itself when running under Windows 2003 Enterprise with PAE enabled.

[TELVM]

Re: Windows XP End of Life Approaching

^ I can think of a couple simple solutions better than condemning hundreds of millions of x86 users to 3.25GB tops per decree:

- Fix the problematic software (the logical step).

- Allow users like you to disable RAM over 3.25GB if that brings them problems.

[mariushm]

Re: Windows XP End of Life Approaching

- Fix the problematic software (the logical step).

Tell me how you're going to fix some third party software that was last updated when Windows 95 was king, but it's still used by a company like IBM or HP which buys shitload of Windows licenses so they can't afford to "blacklist" the software.

- Allow users like you to disable RAM over 3.25GB if that brings them problems.

Give your mom or dad the computer and tell her about PAE and memory and all we discuss here and see their reaction.

Not everyone is a techie or someone knowledgeable about computers or someone CARING about them. For lots of people, the computer is basically like a screwdriver (something used to reach a purpose) or a tv (black box they don't care to do maintenance on)

Solution for these people is just moving on, go to 64 bit OS, like transitioning from from SD TV and RF signals to hd tv and digital inputs.

[TELVM]

Re: Windows XP End of Life Approaching

OK, let me rephrase then as: "Allow users like me to enable RAM over 3.25GB without having to hack the kernel. "

[Topcat]

Re: Windows XP End of Life Approaching

I never thought this day would come....but winXP64 on my home system is now a historical item. I traded it for server 2008 standard r2, which looks and functions very XP-like....but will still be supported. Since I still tinker with web and mysql stuff, some of the server features will actually come in handy....and being @ localhost is kinda nice too!

My office machine was moved to server 2003 x64 about a month ago....and that will be supported until July 2015, atleast.