Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!mit-eddie!rutgers!pyrnj!pyrdc!uunet!wa3wbu!john From: john@wa3wbu.UUCP (John Gayman) Newsgroups: comp.sys.ibm.pc Subject: Re: Is AT mainboard RAM useful between 640K & 1MB? Summary: expanded on MB is strange Keywords: AT, RAM, 640K Message-ID: <670@wa3wbu.UUCP> Date: 13 Nov 88 15:02:49 GMT References: <2663@orca.TEK.COM> Organization: WA3WBU, Marysville,PA Lines: 39 In article <2663@orca.TEK.COM>, mstevens@orca.TEK.COM (Mike Stevens) writes: > I have a generic Taiwanese 286 AT clone which has motherboard RAM > settings for 512K, 640K, and 1MB. I'm using a DTK BIOS with MSDOS 3.21. > When I upgraded from 512K to 1MB, I also upgraded the system configuration > info to reflect the memory size upgrade (yes, I changed the HW switches > too). The system now reports 1MB on powerup (640K base memory, 384K > expanded memory). > > QUESTION: What do I need to do to USE the extra 384K of memory? I I have not seem many motherboards that set their onboard extra memory to "expanded". This is very strange. Most machines will use the extra memory as "extended" memory. Any software applications which can utilize expanded memory (such as Lotus 123) can and should recognize this extra memory you have. There is a slight misconception that this memory lies between 640K and 1MB. It does not. The extra 384K thats usually on the MB lies ABOVE 1MB. This gets a little confusing but basically the memory addresses that lie between 640 and 1M are used for videa addressing, BIOS, etc. You extra 384 actually *starts* at 1MB and thus extents to 1.408 MB. Since this little window between 640 & 1M is pretty much unavailable for applications, it is transparent to the user. I would verify that your extra memory is indeed "expanded" and not "extended". Try installing a RAMDisk in extended memory by adding the following in your CONFIG.SYS: DEVICE=C:VDISK.SYS 380 512 300 /E <-- This "E" puts it in extended. John -- John Gayman, WA3WBU | UUCP: uunet!wa3wbu!john 1869 Valley Rd. | ARPA: john@wa3wbu.uu.net Marysville, PA 17053 | Packet: WA3WBU @ AK3P