Windows 32-bit enforces 4 GB RAM limit through license

ahbleza

Very interesting and extremely technical analysis that argues that Microsoft's 32 bit operating systems are quite technically capable of using more than 4 GB of RAM, but that a license check prohibits this feature, not code.

http://www.geoffchappell.com/notes/windows/license/memory.htm

Microsoft have lost it !

DrDave

Very old news. Vista-ish.

Vitaliy_Kiselev

Very old news. Vista-ish.

It can be old (despite that WIndows 7 is the same), but it is interesting read.

And it is clear that restricting PAE was intentional.

DrDave

Before I changed to 64 bit, I ran different memory sizes on a variety of different flavors of XP and Vista. The are different mods to access memory, and some dedicated people have put some serious time modding the kernel to make it work. Sort of. The problem is, it doesn't work reliably because it isn't just the memory, it is the way the apps access the memory. XP SP0 and SP1 still had PAE mode, as well as some of the 32 bit server flavors. I just think it is a waste of time to run 8gb on a 32 bit system because of random driver calls that crash the system. I suppose if you bought a computer all set up in 32 bit and you wanted more memory--assuming the bios was friendly--you could mess around with it, but it would be faster and easier to install 64 bit OS, and barring a real breakthrough in the kernel, I can't see that you would get stable 32 bit OS because of the drivers. The reason people have sort of dropped the idea is because of the stability issues vs the ease of replacing the OS.

If you want to run 32 bit OS with more memory, you can run server 2008 for example, and you can even run the 64 bit version of XP, which is actually not too bad, but I think it is a waste of time to run those OS. I have one computer running XP for a few legacy programs, if someone offered me a really stable kernel with 8gb support, I would maybe switch, but it would need to be super stable.

In the article, the guy shows that you can use the memory, which ppl knew about anyway--it is available in server editions, so of course everyone knew about it--what he doesn't do is show the apps crashing. We don't always use the best OS, we use the OS with the apps and drivers. Hey, win7 could be worse, but it could be a lot better too.

Vitaliy_Kiselev

@DrDave

I think you did not read carefully whole article. As it has explanation about evolution of code from XP, explanation how PAE works, explanation about drivers things and possible issues and also explanation that main code related to implementation is exactly same in server 2008.

As the guy who made small personal reversing fun I can also tell you that licensing makes also difference in parts related to LAN (on all levels, from buffers and values on low level up to restrictions of connections on top).

DrDave

OK, I will read it again :) I had crashes on my system, but maybe I used the wrong kernel.

DrDave

I looked over my notes--and this was quite a few years ago--and on XP the problem was that if you wanted SP2 the patched kernel did not work, and that on SP1 there were numerous compatibility problems. However, you could have compatibility problems even with the stock kernel. There is another thread on it here based on the original thread http://www.remkoweijnen.nl/blog/2009/06/23/patch-vistas-kernel-to-address-more-than-4-gb-of-memory/ There are a number of prepatched kernels floating around, so ppl can try them if they are interested. I what I am seeing is that for Vista and above, it seems to work pretty well, but of course most people wanted it for XP since no one liked Vista much.

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