elee24@castle.ed.ac.uk (H Bruce) (06/08/90)
Is there any space in the AT memory map for a device such a memory mapped frame grabber ? If so how much and where is it ? If none exists could the 64K window for the LIM EMS be used - or would this be a silly idea (assuming I wouldn't use software that needed EMS). Any info would be much appreciated. Thanks, Henry Bruce
Ingvar.Strand@ext.luth.se (Ingvar Strand) (06/09/90)
In article <4568@castle.ed.ac.uk> elee24@castle.ed.ac.uk (H Bruce) writes: >Is there any space in the AT memory map for a device such a memory mapped >frame grabber ? If so how much and where is it ? >If none exists could the 64K window for the LIM EMS be used - or would >this be a silly idea (assuming I wouldn't use software that needed EMS). >Any info would be much appreciated. > >Thanks, > >Henry Bruce Hi, Assuming you have no ROM-module pluged in, there is 64kb of free memory at address: 0E0000 - 0EFFFF. Ingvar
djb@wjh12.harvard.edu (David J. Birnbaum) (06/11/90)
In article <1475@hagbard.dc.luth.se> Ingvar.Strand@ext.luth.se (Ingvar Strand) writes: > >In article <4568@castle.ed.ac.uk> elee24@castle.ed.ac.uk (H Bruce) writes: >>Is there any space in the AT memory map for a device such a memory mapped >>frame grabber ? If so how much and where is it ? > >Assuming you have no ROM-module pluged in, there is 64kb of free memory >at address: 0E0000 - 0EFFFF. Not on my AT (Compuadd Standard 286/12, Phoenix 3.07 BIOS), nor on many others. My BIOS is a single chip at only really uses 0f800-0ffff. But a copy of the BIOS appears at 0e800-0efff, apparently due to a quirk in the way the motherboard was configured in case there was a 128k BIOS. My lim 4.0 ems board won't use the e000 segment, which means that I can't use it for a page free, remap it with Qram, or do anything else with it. I posted an inquiry about this to comp.sys.ibm.pc last year and got several reports from users with other motherboards and other bioses who had observed the same phenomenon. It may not affect all ATs, but you can't count on your e000 segment being available just because it isn't being used by the BIOS. --David ============================================================ David J. Birnbaum djb@wjh12.harvard.edu [Internet] djb@harvunxw.bitnet [Bitnet] ============================================================