FYI ... DOSBOX just released 0.73 with major improvements - including some new video card & mode emulation. That also means there's been some changes to the conf file key=values. You'll want to check the ChangeLog, FAQ Wiki and so forth.
http://sf.net/project/shownotes.php?release_id=685514&group_id=52551 - ChangeLog
http://dosbox.cvs.sourceforge.net/dosbox/dosbox/README?view=markup - ReadMe
http://www.dosbox.com/wiki/Dosbox.conf - New Settings
For example, "machine=vga" was the old default. The new default is "machine=svga_s3".
Enjoy the classics. Mark S.