시스템변수
- TRAYNOTIFY
- TRAYTIMEOUT
- TRIMMODE
- UCSFOLLOW
- UCSICON
- UCSNAME
- UCSORG
- UCSORTHO
- UCSXDIR
- UCSVP
- UCSYDIR
- UNDOCTL
- UNDOMARKS
- UNITMODE
- USERNAME
- UCSFOLLOW
- VIEWCTR
- VIEWREGIONAUTOSCALE
- VIEWREGIONNAME
- VIEWREGIONNUMBER
- VIEWREGIONSCALE
- VIEWSIZE
- VIEWTWIST
- VISRETAIN
- VPMAXIMIZEDSTATE
- VPROTATEASSOC
- VTDURATION
- VTENABLE
- VTFPS
- WHIPTHREAD