Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!sun-barr!apple!netcom!amdcad!brahms!phil From: phil@brahms.amd.com (Phil Ngai) Newsgroups: comp.sys.ibm.pc.misc Subject: Re: Extended and Expanded memory Summary: EMS 4.0 standard useless Message-ID: <1990Aug22.032056.6380@amd.com> Date: 22 Aug 90 03:20:56 GMT References: <26045@bellcore.bellcore.com> <1990Aug18.110404.28864@cbnewsl.att.com> Sender: usenet@amd.com (NNTP Posting) Distribution: usa Organization: Advanced Micro Devices, Inc; Sunnyvale, CA Lines: 40 In article portuesi@sgi.com (Michael Portuesi) writes: |Okay, my question is: | | Is LIM-EMS 4.0 implemented in software on 3.2 hardware | equivalent to LIM-EMS 4.0 on 4.0 hardware in both features and | performance? | |The reason why I ask this is that I am currently running DESQview 2.26 The answer, particularly given that you are running DV, is NO! The LIM 4.0 spec was written by a committee with many vested interests to protect. It therefore came out with so many optional features as to be almost useless as a standard (unless you are a vendor with lots of 3.2 hardware you don't want to write off). To run DV, several of the "optional" features are mandatory and you seem to be aware of this. |on my Toshiba T1000XE laptop computer. It has an 80C86 and 2.4 MB of |EMS memory. The Toshiba docs say that the hardware is 3.2, and that |the EMS driver supports LIM-EMS 4.0. But DESQview certainly isn't |behaving like there is EMS 4.0 in the machine (yes, I am using XDV). Unfortunately, you are correct. DV is rather painful to use on such a configuration. The best and most trouble-free platform to run DV on is a 386 with QEMM. (but you might try turning on swapping if you simply want DV as a task switcher) |I understand that a big difference between 3.2 and 4.0 is that 4.0 |provides a much greater range of places where the expanded memory can |be mapped into conventional memory. How is this done in software for |3.2 boards? By copying data all over the place? Yuck. I believe the feature of 4.0 you are referring to is "optional" and so 3.2 boards with "4.0" drivers simply refuse to perform the operation. -- Phil Ngai, phil@amd.com {uunet,decwrl,ucbvax}!amdcad!phil