INSIGHT: Atari

Bill Wilkinson

Last month we discussed how to make programs designed for the Atari 400 and 800 load and run automatically on the new XL series without having to hold the option key down. We also looked at a way to make patches into Atari DOS 2.0s to enable it to work with the new enhanced density 1050 disk drive. The procedure is easy, but requires two disk drives. Just type in the source code (the portion printed last month and the continuation found in this issue) using an assembler capable of placing its object code directly in memory. Assemble it after LISTing or SAVEing the source code to disk. After assembling it once, change line number 1000 to read:

1000 .OPT NOLIST, OBJ

and assemble the code once more.

DOS should now be patched. Hit the SYSTEM RESET key and give the DOS command from your assembler. You should now be in the DOS menu (if you're not, something has gone wrong). Format a new disk using option I and then write the DOS files using option H. This will insure that everything is right and will give you a safe copy of your newly patched DOS.

The Tricky Part

There's one more step necessary to finish the procedure. Turn off your computer, put your BASIC (or BASIC XL) cartridge into your machine, and turn the power back on, thus booting the disk that was just formatted. Place a blank diskette into the 1050 drive that you are using as drive 2 and, from BASIC, type the following command:

XIO 254, #1, 0, 34, "D2:"

Drive 2 should now contain an enhanced-density diskette. Now hit the SYSTEM RESET key so that DOS will recognize the new density. Finally, go into DOS and write the DOS files to the new diskette (D2), using option H from the menu.

If everything has been done properly, drive 2 should now have an enhanced-density diskette containing the patched DOS. Once you have this master completed, creating others is simple and can be done with the I and H options in the DOS menu.