Physical Adress Extension and Windows 9x

[Offler]

Im reading the article about Win98 architecture which dencorso posted here. Very interesting. Im interested mostly in Virtual memory management.

There are certain limits. 640kb for real-mode deviced, 4mb to 2gb Win32 apps, 2-3 gb core system components, 3-4gb Ring 0 components.

Are there any information how much memory can core and ring 0 components use up?

To me it seems that for each win32 system (From win95 to XP and Vista 32bit) should be best to have 4 gigabytes of ram to assure that disk shall NOT be accesed and to keep all system parts "aboard" in memory, without affecting memory reserved for 32bit applications.

The fight between Singlecore and Dualcore CPUs is a bit different battlefield, but ideal Win32 machine to me is using Dualcore processor, with 4 gigabytes of ram and Windows 5.x, no matter that system shows only 3.2gb. Or will be memory in this case bit wasted? The goal is to use disk only as a peripheral device which is not intended to use as random access memory (swap).

To solve thes it is good to know how intensly can windows use up the memory which it reserves.

[EyesOfARaven]

I was originally under the impression that Windows licensing supports 4GB of addressing for RAM, whether it be BIOS, VRAM, SysRAM etc.., and that anything above 4GB when you total that up was deducted from the SysRAM and ignored. Apparently this is not the case, with 64-bit addressing under 32-bit Windows, so this raised a question for me:

How does Windows do 64-bit mapped memory? What does it do with it? Does [only] the system make use of it? Do modern applications use calls to allocate it if available? Does the underlying system allow the use of it regardless of how the program was written?

I assume due to it's age and inherent limitations, Windows 98 doesn't share in modern versions of Windows' possible API for 64-bit address space, so if it still maps the RAM off to there, I assume it just sits there, waiting for some application to claim it (such as your RAMDisks, rloew)?

BTW: rloew: I wish there was some way I could afford to get some of your apps.. I am so out of money, but It'd be great to get Win98 working efficiently on one of my modern boxes. Really impressive work you've done.