Classic Computer Magazine Archive ANTIC VOL. 3, NO. 12 / APRIL 1985

From the ABCs of Atari Computers
by David Mentley

DISABLE KEYBOARD - POKE 16,255 to completely DISABLE the KEYBOARD. This will prevent mischief by those you wish to keep away from your programs.

SAVE "S:" - You can use the SAVE"S:" command to examine the tokenized BASIC prograam which you have in memory Simply LOAD in a BASIC program, and while in the immediate mode, type SAVE"S:" <Return>. The screen will clear and the tokenized program will be listed on the screen.
One further extension of the SAVE "S:" command is to examine the contents of your Atari's memory by using the screen. You must change the value of the registers which store the end of the BASIC file. You can then list out all memory to the top of memory ( FFFF). To do this, POKE 140, 255 and POKE 141, 255, then type SAVE"S:". When this has been done, your program will list, then all free memory, followed by the BASIC cartridge and the Operating System.

DOS VECTOR - When you type DOS in BASIC, a pointer is followed to a routine which loads in the DUP.SYS package of utilities. You can borrow this vector for your own use. The location of the DOS vector is in RAM at locations 10 and 11 ($0A and $0B). Since they are in RAM in page 0, you can change them to point anywhere you want. You could point it at the start of BASIC (40960) or at a subroutine you loaded into memory. Remember, all you have to do to enter the routine once you have changed the vector is type DOS. After you set 10 and 11 they will be reset when you press SYSTEM RESET unless you do the following. Locations 5446 and 5450 ($1546 and $154A) contain the value that the warmstart routine places back into 10 and 11. So if you POKE your DOS VECTOR location into 5446 and 5450 (LO-HI), you will keep your new pointer until you turn off the power.

LEFT-HANDED JOYSTICK - You can convert an ordinary Atari joystick to a lefty model by merely unscrewing the base and transposing a few connectors. The button will be on the top right side when you are finished and all of the direction labels on the front should be changed for consistency. The top will become the right side. When you take the bottom off the case, you will see a column of colored connectors. Use the chart below to transpose the wires and put your lefty model back together.
      Right      Left
      brown      blue
      white      brown
      black      black
      blue       green
      green      white
      orange     orange

From ABCs of Atari computers by David Mentley (available through the Antic Catalog in this issue). Reprinted by permission of Datamost, Inc.