Re: Question about UMBs

>   I learned this several years ago, but I've never done anything with it 
> since, so... I'm wondering how a UMB provider informs DOS that there's 
> now memory about the video buffer at A0000-BFFFF? 

XMS function 0x10 (see RBIL int2f/4310)

> is it possible to create a .sys file, loadable by the 
> DEVICE command in config.sys, that won't take any memory after 
> initialization? Meaning, it loads, does its job, and is completely out 
> of memory afterwards.

return installation error and set memory required=0, 
and you won't get installed.

tom