CHKTIME 1ST SUN IN APRIL 0300, LAST SUN IN OCT 0300, SUN 0300
IF ERRORLEVEL 3 GOTO SETEVENTS
IF ERRORLEVEL 2 GOTO DSTOFF
IF ERRORLEVEL 1 GOTO DSTON
GOTO NOTTIME
:DSTOFF 
rem "Fall back" on the Last Sunday in October, but only the first time
IF EXIST DONE.DAT GOTO SKIPIT
DSTIME OFF
COPY AUTOEXEC.BAT DONE.DAT
GOTO SETEVENTS
:SKIPIT
DEL DONE.DAT
GOTO SHUTDOWN
:DSTON 
rem "Spring forward" on the 1st Sunday in March
DSTIME ON
:SETEVENTS 
SMART10 /S A1 cancel OFF @ 0310
SMART10
:SHUTDOWN
SMART10 /S A1 off
:NOTTIME
rem done!