Windows 95 Coexisting with OS/2 Warp

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Last Updated: 9th September, 1995

The following information is derived directly from a text file used by IBM' OS/2 Support that helps IBM's customers configure OS/2 Warp and Windows 95 so that neither operating system conflicts with the other. Please read the disclaimer below.

Please read entire document for full explanation of procedures.

When installing Windows95, there are steps you should take to make the coexistence of Windows95 with OS/2 Warp smooth.

It's best not to install Windows95 over Windows 3.1.

During the Windows95 installation, select a directory other than the Windows 3.1 directory if you want WIN-OS/2 support in the OS/2 Warp for Windows version. The OS/2 Warp Fullpack versions of WIN-OS/2 support are not affected by the Windows 95 installation. Windows95 will copy over Windows 3.1 files and they are not recoverable unless you have diskettes or make an archive during the installation.

What if you installed Windows95 over Windows 3.1?
There's a simple solution for those with the OS/2 Warp for Windows versions. If you have Windows 3.1 diskettes, you can install Windows 3.1 to a separate subdirectory. Then Dual Boot or use Boot Manager to start OS/2 and run Selective Install. Choose to reinstall the WIN-OS/2 support and point to the new Windows 3.1 subdirectory.

What error occurs when you start WIN-OS/2 after installing Windows95 over Windows 3.1?
The error you get trying to start any WIN-OS/2 session which points to Windows95 code is a SYS3175 dialog.

What error do I get if I try to start a Windows95 32-bit application from WIN-OS/2?
If you migrate any Windows95 applets or applications to your WIN-OS/2 environment, you get an Unexpected DOS Error: 23. Click on OK to bypass the information message. You cannot run 32-bit Windows95 applications under OS/2 Warp or Windows 3.1.

How do I migrate 16-bit Windows applications that have been installed from Windows95?
In order to ensure a stable application environment, Windows applications should be reinstalled under OS/2 Warp to the same directory they were installed to under Windows95 (to save space).

The Windows95 installation says Boot Manager will no longer be usable. Is that true?
During the Windows95 installation, some "information messages" appear if Dual Boot or Boot Manager are present on the system. Always press continue to bypass these errors. There are no bad effects from having OS/2 on the same partition as Windows95. Boot Manager is no longer the ACTIVE partition, but can be made active by following the steps below:
 * 1) Start FDISK from any prompt.
 * 2) Change the 1MB non-DOS partition (Boot Manager) to active.
 * 3) Save the settings.
 * 4) Shutdown and restart the system. You should now get the Boot Manager menu.

How does Dual Boot work with Windows95?
If you start the Windows95 installation from DOS on a Dual Boot system, there should not be any problems with Dual Boot between Windows95 and OS/2. To start OS/2 do the following:
 * 1) Open a DOS prompt from Windows95.
 * 2) Type: C:\OS2\BOOT /OS2
 * 3) Answer Y to continue.

How do I get back to my original DOS setup once I've installed Windows95?
To get back to the original DOS CONFIG.SYS system files, the ones you started with before the Windows95 installation, do the following: Return to The Warp Pharmacy:Software
 * 1) Shutdown Windows95 and restart it.
 * 2) During startup, as soon as you see "Starting Windows95..." press F8 to get the Windows95 recovery screen.
 * 3) Select the last option on the list, Previous Version of MS-DOS.
 * 4) You are now using the same DOS CONFIG.SYS that you started with.