VOGONS


First post, by feipoa

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I remember reading that Windows 9x uses memory from the top, down (e.g. if you have 32 MB of memory, the start of memory usage occurs from the 32nd MB, then fills the 31st MB, then the 30th MB, etc), such that if your system contains more memory than your system can cache (not enough cache), you will receive a performance hit. This is pretty evident to check for using CPUMark99, for example.

I also recall that DOS, on the other hand, starts using memory from the bottom, up, such that you will not immediately receive a performance hit for the MB's closest to the bottom.

Does anybody know which order Windows 3.11 uses memory in, that is, the DOS order or the Win9x order? Thanks!

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Reply 2 of 3, by Jo22

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AfaIk, it might depend on himem.sys also. That's what Win 3.x gets its memory from (though the actual managment is done by 3.x itself).
I think Windows 9x himem.sys and DOS 6.x himem.sys differ in the order they address physical memory..
Edit: Re: A problem when trying to install a Living books game on Windows 3.1 on PCem.
Edit: So yes, you're right. :) DOS=upwards (bottom-up), Win9x=downwards (top-down).
Windows 3.11 comes with a copy of DOS 6.x himem.sys, so it is likely that it follows its convention.

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Reply 3 of 3, by feipoa

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I was hoping that someone has specifically tested for this, so I will add it to my ever-expanding list of curiosities to investigate. I suspect the memory use order is that same as DOS 6.22, but I want to be sure.

Plan your life wisely, you'll be dead before you know it.