10 '"SYS" Returns from basic to DOS with a clean screen
20 DEF SEG=0:POKE 108,&HD3:POKE 109,&H15:POKE 110,&H7:POKE 111,&H3
32 SCREEN 0,0,0:WIDTH 80:COLOR 6,0,0:KEY OFF:CLS:UP$=STRING$(1,30)
33 LOCATE ,,1,12,13:DEF SEG=0:IF PEEK (&H410)= 109 THEN LOCATE ,,,6,7
34 DEF SEG=64:POKE 23,128:DEF SEG:CL$=STRING$(79,0):Q$=CHR$(34)
40 SOUND 500,6:CLS:LOCATE 24,1:SYSTEM:END