: WIPE BLK( 1024 0 FILL BLK!! ;
: WIPED? ( -- f )
1 ( f ) BLK) BLK( DO
I C@ IF DROP 0 ( f ) LEAVE THEN LOOP ;
: COPY ( src dst -- )
FLUSH SWAP BLK@ BLK> ! BLK! ;
: FREEBLKS? ( b1 b2 -- )
1+ SWAP DO I BLK@ WIPED? IF I . SPC THEN LOOP ;