Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!tut.cis.ohio-state.edu!cs.utexas.edu!usc!apple!amdahl!drivax!liberato From: liberato@drivax.UUCP (Jimmy Liberato) Newsgroups: comp.sys.ibm.pc Subject: 4.0 LIM and Extended Memory (was: can I put four floppies in an AT) Keywords: everex ram memory extended expanded Message-ID: <5YCCRWV@drivax.UUCP> Date: 8 Jan 90 03:02:58 GMT References: <10767@ucsd.Edu> <4597@hydra.gatech.EDU> <88@slvblc.UUCP> <1990Jan5.171736.15733@druid.uucp> Reply-To: liberato@drivax.UUCP (Jimmy Liberato) Organization: Digital Research, Inc., Monterey, California Lines: 44 darcy@druid.uucp (D'Arcy J.M. Cain) writes: >In article <88@slvblc.UUCP> dick@slvblc.UUCP (Dick Flanagan) writes: >> >>I have two of the Everex RAM-3000 boards. They are EXTended memory boards, >>*not* EXPanded memory boards. LIM in any form is not supported on the board. >This is almost true. Although expanded memory was originally designed as >a hardware bank switching scheme, the LIM spec allows any sort of memory >to be used as expanded. There are many programs that allow any type of >extended memory to be used as expanded and I believe that Everex includes >one with the RAM-3000. This is the LIM support referred to. Right. When they started including a LIM 4.0 driver with it they started calling it Ram 3000 Deluxe. As others have mentioned, there are some programs that balk at software emulation of 4.0 LIM. The cheap boards are always either 3.2 LIM with a 4.0 driver or extended memory with 4.0 emulation. One interesting point, old AST Rampage EEMS boards give true hardware level support for LIM 4.0 when paired up with a new 4.0 driver. On a related subject, I am now seeing high DOS memory (640-1024K) being refered to as extended memory, at least on AT class machines with 1 Meg of memory on the motherboard. The POST test on an DTK AT clone even categorizes this memory as extended memory. I have heard it refered to variously as high memory, video memory, and bios memory. All these make some sense but is it strictly correct to ever refer to these blocks of memory as extended? Is this simply a loose and generic use of the term? Is this physical memory simply being mapped beyond the FFFFF address, that is does the extra 384K actually start at the 100000 address? If I were to add a 1 Meg extended memory board would I actually have 1408K? Am I confusing physical memory (the 384K of extra ram in those chips) with logical memory (the reserved adresses for video and bios)? I think I have a fairly good grasp of all of this but this is really nagging at me and I can't seem to find an explanation or can't properly explain my confusion. So if anyone understands what I am getting at please enlighten me! -- Jimmy Liberato ...!amdahl!drivax!liberato "Truly great madness can not be achieved without significant intelligence." -Henrik Tikkanen