Virtual OS/2 International Consumer Education

August 1998


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OS/2 Technology Issues

Part 5

Multiple Boot Configurations

by: Dan Casey (
August 15 1998

This series of articles is not about recommending specific hardware and/or software. It's about information.

Beginning with Warp 3, IBM introduced a new feature to OS/2 users; the ability to boot different configurations and the ability to select which configuration you want to boot from a startup menu.

I think we all know that pressing <ALT><F1> when the white rectangle appears at bootup will bring us to a "Recovery" menu. From there you can select to boot to a command prompt, or to reset video to Standard VGA.

But how many of you know that you can modify that menu, and add a Custom CONFIG.SYS file to it?

This is a little-known but (fortunately) well documented feature that could come in real handy, especially if you use a Laptop computer with a Docking Station or Network. You can use the default CONFIG.SYS file to boot the system normally (whatever your most-used configuration is) and use the Custom CONFIG.SYS file to boot it when you need a different configuration (such as using the Laptop in a Docking Station, or using the Laptop without the LAN configuration). The possibilities are only limited to whatever you need to do.

For the purposes of this article, we'll use, as an example, a Laptop that is to be used both Stand-alone and connected to a LAN, with different CONFIG.SYS files for each use. The "normal" CONFIG.SYS file will be for use in Stand-alone mode, while we'll use CONFIG.L for use when attached to the LAN.

Step 1
Copy the existing CONFIG.SYS file to the \OS2\BOOT directory, and rename it to CONFIG.n where n is any letter or number EXCEPT C, M, V, X, 1, 2 or 3.
For this example, we used CONFIG.L

Step 2
Edit the file \OS2\BOOT\ALTF1BOT.SCR

This file is the Bottom of the ALT-F1 Recovery Menu. It is also Write-Protected, so you'll have to change the attribute before you can edit it. From an OS/2 Command Prompt, type:


If you boot from a drive other than C:, substitute the drive letter in the command.

Now, using whatever text editor you like (E.EXE works just fine), Edit the file ALTF1BOT.SCR and add a line that gives you a description of CONFIG.L that you'll recognize at boot. Add 3 spaces (press the spacebar 3 times) at the beginning of the line, so it will line-up with the choices already present (in the ALTF1MID.SCR file).

L) CONFIG.L Loads LAN drivers when chosen.

Save the file and exit the editor.

Step 3
Edit the CONFIG.SYS and CONFIG.L files.

Let's assume that the original CONFIG.SYS file always booted with the LAN drivers. Now, we need to have it boot WITHOUT the LAN drivers. Edit the CONFIG.SYS file and REM out the lines that load your LAN drivers. On my system, this would be:


Save this file as CONFIG.SYS and exit the editor.

Step 4
Set the Recovery Menu to always appear at boot.

This, of course, is optional. If you choose not to do this, you can always press <ALT><F1> when the White Rectangle appears to get to the menu.

RMB click anywhere on the desktop, and when the menu pops up, select PROPERTIES. Click on the ARCHIVES tab, and select:
Display Recovery Choices at Each System Startup.

That's all there is to it. You now have 2 different boot configurations, and a method to choose which one you want to use at each startup. NOTE: If you install a new application that modifies your CONFIG.SYS file, you'll need to manually edit the other CONFIG file to match, or else the app will only work when you boot to the configuration in use when you installed it.

NOW .... here's where it can get interesting. Say you want to install some applications that you would use ONLY when connected to the LAN. Besides modifying the CONFIG.SYS file (or in this case, the CONFIG.L file), you also change the User INI file (OS2.INI) to update the desktop and WPS. But you don't need this application when not connected to the LAN, and you don't want it to appear on the Desktop when you boot the Stand-alone configuration.

In CONFIG.SYS (or in this case, CONFIG.L) there is an Environment Variable that is set at boot.


Copy the OS2.INI file to, say, OS2L.INI (L for LAN) and edit the CONFIG.L Environment Variable to reflect the other copy of the INI file.


Now, when you boot to the LAN configuration, you are not only using a different CONFIG file, but a different INI file as well. Any changes made to either of these files will only be evident when booting this configuration. Booting the standard (default) configuration will not reflect any changes made while in the other configuration. You can also change the Environment Variable for the System INI (OS2SYS.INI) file as well.

Other possible uses for this is BETA testing applications. Use another copy of CONFIG.SYS (such as CONFIG.B (for BETA) and OS2B.INI and OS2SYSB.INI) and you'll not have to worry about corrupting your INI Files because you used a BETA copy of an application that has a serious bug in it.

Should you choose to boot a configuration that, basically, starts from scratch, without destroying your current setup, you can copy the file CONFIG.X to, say, CONFIG.B (CONFIG.X is the config.sys file your system uses when you choose "F2 - Go to command line, (no files replaced, use original CONFIG.SYS)" from the Recovery Menu). This file is Write Protected, so, after you make the copy, you'll have to run:


Then, create new INI files using the built-in utility MAKEINI.



Then, edit the CONFIG.B file and replace the values for the Environment Variables:




This will give you a config.sys file equivalent to the settings and configuration you had when you first installed Warp, as well as the original OS2.INI and OS2SYS.INI files. You can, in effect, start up a configuration of Warp that is as it was when you first installed it.

You can even choose a configuration that allows your Warp system to appear like an OS/2 2.0 Desktop, an OS/2 1.3 Desktop or a Windows 3.x Desktop by creating unique INI files using the MAKEINI utility and editing the CONFIG.n file to reflect the changes you wish to use in the Environment Variables.

There is no guarantee that using this configuration will prevent damage to your file system if you are using a misbehaving BETA application. It will prevent corruption in your default INI files, but the only SAFE way to test BETA products is by actually booting a totally different Warp system using Boot Manager (or another Boot Utility), thus isolating the 2 Operating System partitions.

Information and Instructions in this article were found in the OS/2 Warp 4 Online Documentation, in the printed book "OS/2 Warp Unleashed, Deluxe Edition" and "The Warp Databook (at Even though OS/2 Warp Unleashed was written for Warp 3, it is still one of the best 3rd party Printed books available for Warp systems. And the Warp Databook is constantly updated to reflect changes, upgrades and enhancements to the Warp Operating System, making it an excellent source of up-to-date information on OS/2 Warp.

VOICE is, basically, a volunteer organization. We are supported, almost entirely, by our members. We are OS/2 users helping OS/2 users.
If you'd like to contribute to our effort, Membership information is available on our Website. And if you'd like to contribute to this series of articles, E-mail me with a brief description of your idea. Of course, we'd like to have contributions from our members, but membership is not a requirement for contributing to our cause.


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