Hi Mateusz, > Actually, by taking a closer look I did find the function 0Ch from both > the XMS 2.0 and 3.0 standards. This function returns the physical > address (called "base address" for the occasion) of the allocated XMS > block as a 32bits integer. > > Now, I could imagine an application (like DOS4GW) that gets such address > and puts it into a 24bit field. Such behaviour would effectively limit > an application to being able to use only the lowest 15MB of the XMS memory.
Wikipedia says: https://en.wikipedia.org/wiki/DOS/4G * DOOM was the first game to make dos/4g or dos/4gw popular * it was limited to 64 MB of memory So I can imagine that Doom uses a really old version of dos/4gw, which is even more likely to have issues with "too much RAM" ;-) "We expect to be updating the DOS extender to use the extended XMS and VCPI calls that allow access to greater than 64MB" That sounds as if it is in any case limited to XMS 2. Have you made some comparisons between XMS-only and EMM386-style behaviour of DOOM? http://www.tenberry.com/dos4g/rn4g.html Version 2.01 (1996) mentions some fixes for systems with above 64 MB of memory and even for properly supporting 64 MB in the first place. I repeat my advice of using DOS32A instead of working around DOS/4G. DOS32A is free open source while DOS/4G came in version 1.97 with old Watcom compilers while 2.01 was only available as paid update: http://www.tenberry.com/dos4g/watcom/prices.html Which version does your copy of DOOM use? Cheers, Eric ------------------------------------------------------------------------------ Monitor 25 network devices or servers for free with OpManager! OpManager is web-based network management software that monitors network devices and physical & virtual servers, alerts via email & sms for fault. Monitor 25 devices for free with no restriction. Download now http://ad.doubleclick.net/ddm/clk/292181274;119417398;o _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
