"This is in response to a question ["Ask The Readers," COMPUTE!, February, 1982, #21] asked by Mr. Michael A. Ivins concerning the saving of screen data to cassette [on the Atari]. The following program can be used as a subroutine to do just that.

0 POKE 82,0:GR. 0
10 OPEN #3,12,0,"E:":OPEN #5,4,0,"K:"
15 ? "Do you want to Make or Retrieve a picture?":
        GET #5,A: IF A = ASC("R") THEN 200
20 ?"Use the keyboard to draw": ?"Hit RETURN to save to cassette"
30 GET #3,A:IF A = 155 THEN 100
40 GOTO 30
99 REM SAVE TO TAPE
100 POKE 752,1 :? CHR$(126);:OPEN #4,8,0, "C:":
       REM "D:FILESPEC" FOR DISK
110 FOR Y = 0 TO 23
120 FOR X = 0 TO 39
130 LOC. X,Y,Z
140 PUT #4,Z
150 NEXT X
160 NEXT Y
170 CLOSE #3:CLOSE #4:CLOSE #5
180 END
199 REM LOAD A PICTURE FROM CASSETTE
200 ?"(ESC CTRL CLR)";:OPEN #4,4,0, "C:":REM "D:" FOR DISK AGAIN
205 OPEN #6,8,0, "S:"
210 FOR I = 1 TO 960
220 GET #4,A:PUT #6,A
230 NEXT I
240 CLOSE #4:CLOSE#3:CLOSE#2:CLOSE#5:CLOSE#6
250 GOTO 250

The cassette version takes only 50 seconds and the disk version is probably much faster.

Also, for all of you who have the assembler/editor cartridge there is a command to save source programs to cassette. It is LIST#C<, to save and LOAD#C to retrieve. Just ignore the inevitable ERROR -4 that you get when loading."