APPENDIX TWELVE



     250 PRINT "PRESS RETURN TO TEST IT"
     260 PRINT :PRINT :PRINT
     270 PRINT "POKE 57344,1"
     275 PRINT "{5 SPACES}$E000=1":PRINT
     280 PRINT "POKE 57344,0"
     290 POSITION 1,4
     300 DATA 169,0,133,203,133,205,169
     310 DATA 192,133,204,169,64,133,206
     320 DATA 160,0,177,203,145,205,200
     330 DATA 208,249,230,206,230,204,240
     340 DATA 12,165,204,201,208,208,237
     350 DATA 169,216,133,204,208,231,8
     360 DATA 120,173,14,212,72,169,0
     370 DATA 141,14,212,173,1,211,41
     380 DATA 254,141,1,211,169,192,133
     390 DATA 206,169,64,133,204,177,203
     400 DATA 145,205,200,208,249,230,204
     410 DATA 230,206,240,12,165,206,201
     420 DATA 208,208,237,169,216,133,206
     430 DATA 208,231,104,141,14,212,40
     440 DATA 104,96

     You can make this into a machine language AUTORUN.SYS file
     by changing the loop to 1634, removing the number 104 in line
     440, and deleting the USR call in line 220. Go to DOS and do a
     binary save (option K) at addresses $600-$662, with a run ad-
     dress of $600. This will change your ROM OS into a RAM OS ev-
     ery time you boot up that disk. Pressing RESET switches the OS
     back to ROM. The machine language source code for this short
     program (also by Joe Miller) is included here because I felt it
     important for machine language programmers to see how this
     is done:

     ;Move XL OS ROM into RAM
     ;
     ;RAMROM--Installs the XL ROM-based
     ;  OS in RAM at the same address
     ;  space. This is useful for
     ;  making small patches to the
     ;  OS or for experimenting with
     ;  new design concepts, such as
     ;  multitasking, window
     ;  management, etc.
     ;
     ;    By Joe Miller.
     ;
     ;This version is configured
     ;as an AUTORUN.SYS file.
     ;
     SOURCE  EQU     $CB             ;zero page usage