I am not proposing to make an incompatible method.  I am proposing to make
one that:
 
1.  Is more likely than any other to actually achieve true compatibility.
 
2.  Extends further the data compactions of other methods.
 
PRINT, PUNCH, DISK, CARD, and NETDATA never achieved this, and I doubt they
every will completely do this.
 
I never heard of RMSG.
 
RFC822 is not a file transmission method, although with a special extra
layer in between, any of the above can be put inside RFC822.