sentences:  This allowed it, on 286 systems with supported chipsets and on 386 systems, to provide significantly more free conventional memory than any other DOS.Once drivers for a mouse, multimedia hardware and a network stack were loaded, an MS-DOS/PC DOS machine typically might only have had 300 to 400 KB of free conventional memory – too little to run much late-1980s software.In contrast to this, DR DOS 5.0, with a little manual tweaking, could load all this and still keep all of its conventional memory free – allowing for some necessary DOS data structures, as much as 620 KB out of the 640 KB.