Classic Computer Magazine Archive ANTIC VOL. 8, NO. 2 / JUNE 1989

AUTORUN Selector

Total control over your settings

By Jason Strautman

Ever known the frustration of trying to get to DOS from a disk with a AUTORUN.SYS file on it? AUTORUN Selector lets you disable the AUTORUN file on booting, with just the press of a button. This short BASIC utility (translated from machine language) works on all 8-bit Atari computers with disk drive.

If you're like me, you've got a lot of disks with AUTORUN.SYS files on them. And if you're like me, sometimes you need the familiar DOS menu for file copying and other housekeeping tasks. So I always had to keep a separate disk with no AUTORUN files, just DOS.SYS and DUP.SYS, for the times I needed the DOS menu. This seemed like a waste of a disk, so I designed a short solution, AUTORUN Selector.

When you append AUTORUN Selector to your favorite AUTORUN.SYS files, the next time you need to go to DOS, just press the [SELECT] key as you boot the disk and AUTORUN Selector will skip over your AUTORUN.SYS file and load DOS.


Type in Listing 1, SELECT.BAS, check it with TYPO II and SAVE a copy before you RUN it. When RUN, SELECT.BAS creates the machine language program, SELECT.EXE, and writes it to your disk. Antic Disk Subscribers will find SELECT.EXE on the monthly disk.

Listing 2, SELECT.M65, is the MAC/65 source code. You do not need to type it in to use AUTORUN Select.

Before AUTORUN Selector willl work, you must appended the SELECT.EXE file to the top of the AUTORUN.SYS file you want it to work with. Here's how to do it:

1. Make backup copies of SELECT.EXE and the AUTORUN.SYS file you need to modify. Keep the originals in a safe place--we'll work with the backups.

2. Type DOS to bring up the DOS 2.0 (or DOS 2.5)menu. Make sure SELECT.EXE and your AUTORUN.SYS file are on the same disk.

3. Type the following:



This copies your AUTORUN.SYS file onto the end of SELECT.EXE. The SELECT.EXE file now contains AUTORUN Selector and a copy of your AUTORUN.SYS file.

4. Delete the AUTORUN.SYS file. You don't need it anymore because SELECT.EXE contains a copy of it.


This AUTORUN.SYS file is the finished product. The AUTORUN.SYS file will load and run just as it did before, whenever you boot the disk. If you press the [SELECT] key while booting, AUTORUN Selector will skip over your AUTORUN.SYS file and load DOS instead. Make sure you have the DUP.SYS file on your disk when you do this.

AUTORUN Selector will also work whenever you press [SELECT] and any other console key. For example, XL/XE owners who want to use AUTORUN Selector with a program that doesn't use BASIC can simply press both the [SELECT] and [OPTION] keys while booting.

AUTORUN Selector first checks DOSVEC (10, $0A) for the address to branch to if DOS is selected. Next, it takes the value from CONSOL (53279, $D01F) and determines which console keys are being pressed. If bit 1 of CONSOL is clear, the [SELECT] key is being pressed. This is true even when the [SELECT] key is pressed along with other console keys.

If [SELECT] is not pressed, AUTORUN Selector continues to load the rest of your AUTORUN.SYS file.

Otherwise, if [SELECT] is pressed, AUTORUN Selector jumps to the address it took from DOSVEC and loads DUP.SYS which contains the DOS menu.

Jason Strautman lives in San Antonio, Texas and has been programming for the last five years. This is his first appearance in Antic.

Listing 1: SELECT.EXE Download

Listing 2: SELECT.M65 Download / View