$currpos = 0;
while ( read( $dpf, $input, 80, $currpos ) )
{   # get 80 characters from $currpos till EOF
   $input =~ m/($RID)(.*?)(?:$RID)/g;  #grab a code, data and set pos
   # test $1 and $2 for errors
   $currpos = pos( $input )  # set pos in file to beginning of next id
}