jdb@reef.cis.ufl.edu (Brian K. W. Hook) (03/14/91)
Okay, I have been running saying that the VGA memory area is at A000, right? And this is above 640K....but what about systems with 512K? Where do all the ROM extensions and stuff go? Are they on the cards? If they are, is that memory above 640K really there as far as applications are concerned? Couldn't you recover it for use with applications? Just wondering, Brian
imp@Solbourne.COM (Warner Losh) (03/14/91)
In article <1991Mar13.231856.4307@Solbourne.COM> imp@Solbourne.COM (Warner Losh) writes: >I suppose that it could. However, the standard MS-DOS that get >shipped with PCs would recognize it. ^^^ NOT Sorry about that. Warner -- Warner Losh imp@Solbourne.COM We sing about Beauty and we sing about Truth at $10,000 a show.
klingler@triton.unm.edu (David Klingler) (03/14/91)
First let me make sure I understand your question: On most modern mother boards, any memory left over after the standard 640k base memory is assigned can be configured in some combination of 3 different ways: 1) Extended Memory, which is in the 1 meg+ region of the address space of an AT class or higher computer. 2) Expanded (LIM spec) memory, which sits out by itself but has a kind of "movable window" that shows up in the under 1 meg address space. 3) Shadow RAM, Hi-Mem(?), etc, (I'm not too sure about the terms used here) This memory actually goes in the 640-1meg space, which is what I think you are talking about. They serve 2 functions, first (Shadow RAM) your machine may copy the contents from the slow ROMS that are in your machine during boot-up time and copy them to your much faster RAM. This way your machine is accessing this fast RAM when it thinks it is accessing slow ROMs. Second, there is a lot of blank spaces in the 640-1meg area that is between these blocks of ROM. You can fill this with RAM then SOME programs that are designed to go look for it can use it. It is popular to load TSRs in this space. Also DOS extenders, Desqview & Windows seem to know how to put this to good use too. D