Install two Windows OSs on the same machine—but be careful

When Microsoft President Steve Ballmer announced Windows 2000 Professional's (Win2K Pro's) release to manufacturing (RTM) last year, he called it "the best operating system for business users, period." In most respects, this claim is true; however, Win2K Pro isn't completely compatible with hardware and software for Windows 9x. I'm still waiting for a Windows 2000 (Win2K) scanner and fax driver for my Hewlett-Packard HP OfficeJet 710 all-in-one device, and I use flight-simulation software that won't run on Win2K. So I can't yet dump Win98, much as I'd like to, and judging by reader mail, I'm not the only one in this situation. Thus, you might want to know how to set up a dual-boot environment that lets you switch between Win2K Pro and Win98.

Preparing a Dual Boot
Before you set up a dual boot, plan the disk partitions and formats. Win2K and Win98 are compatible with the 16- and 32-bit FAT formats, but only Win2K understands NTFS 5.0; therefore, you'll need at least one FAT16 or FAT32 partition to set up a Win2K Pro and Win98 dual boot. Moreover, unless you use a third-party product such as PowerQuest's PartitionMagic to gain more flexibility in switching among partitions of various formats, the C drive's partition needs to be FAT16 or FAT32 because both OSs use the C drive during the initial boot process. (For information about PartitionMagic, see Mark Minasi, "PartitionMagic," Summer 1999.)

Microsoft doesn't support using the same partition for Win2K and another OS. Partitions need to be separate because Microsoft doesn't put all OS elements in one directory structure. Directories exist for shared programs, as well as for documents and settings. If you install Win2K and Win98 on the same partition, each OS will try to install components in the same place—and you can't guarantee that all components are fully compatible between systems. (For more information about configuring multi-OS environments, see Sean Daily, "Mastering Multibooting Madness," July 1999.)

One refinement that I've been playing with is putting each OS on a separate disk. In "Virtual Memory Tuning," December 1999, I explain how I discovered that Win2K performs better if you put the virtual memory paging file on a separate disk. On my system, that disk also contains Win98.

After you arrange the partitions, you can add the second OS to your system. But unless you're creating a dual boot from scratch, you need to back up your data files and make sure you have the required diagnostic and recovery disks. Setting up a dual boot is usually a benign procedure, but in some cases you might wind up with a system that doesn't start properly. If you plan to add Win98 to a Win2K Pro system, you need to use Win2K Backup to create an Emergency Repair Disk (ERD), which lets you recover the system if the Registry becomes corrupted as a result of the Win98 installation. If you're adding Win2K Pro to a Win98 system, you need to create a Win98 boot disk from the Control Panel Add/Remove Programs applet.

Easy Dual Boot: Adding Win2K Pro to Win98
Creating a dual boot is easy if you start with Win98 already installed—just run Win2K Pro setup and decline the option to upgrade, as Screen 1, page 162, shows. Also, decline the option to convert the partition to NTFS; Win98 can't read or write to NTFS partitions. If you inadvertently convert the root partition (i.e., C drive) to NTFS, Win98 won't be able to boot. You can use NTFS on other partitions, but Win98 won't see them. Win2K Pro setup should proceed as usual, and the system will give you the option to boot either Win2K Pro or Win98 on system startup. Adding Win2K Pro to a Win98 system is easy, so I recommend installing Win98 first when you create a dual-boot system from scratch.

Not-So-Easy Dual Boot: Adding Win98 to Win2K Pro
Adding Win98 to a Win2K Pro setup is more difficult. This configuration will work only if the root partition is FAT16 or FAT32 and the partition on which you install Win98 is also FAT16 or FAT32. The main problem is that Win98 setup won't run from Win2K. To work around this problem, you need a Win98 boot disk. The full installation version of Win98 includes a boot disk; however, if you're installing an upgrade to Win98, you need to create a Win98 boot disk on another system.

If you install the Win98 upgrade, the system asks you during setup to supply the original Win95 media or select a directory that includes Win95 components because Microsoft markets the upgrade to people who already have Win95. The full retail version of Win98 costs more than the upgrade, but I think it's worth the money if you're performing a first-time installation. Either way, run Win98 setup and follow the directions, putting Win98 on a separate partition from Win2K.

Before you add Win98 to a Win2K Pro system, you need to create a Win2K ERD because Win98 will overwrite the Win2K Pro boot sector on your C drive, eliminating the option of booting Win2K Pro on system startup. To restore that option, you need the ERD and the Win2K Pro boot disks. Make the boot disks by running makeboot.exe from the boot disk directory on the Win2K Pro CD-ROM, as Screen 2 shows. You'll need four blank high-density disks. After you create the boot disks, shut down the system, put the first boot disk in your system's A drive, and restart the system. The system will prompt you for the other disks. Select the option to repair a damaged Win2K Pro installation. The system will prompt you to insert the ERD. Win2K Pro setup will replace the files on the boot partition, and you should have the option to boot either Win2K Pro or Win98 on the next restart. If the system doesn't give you the option to boot either OS, manually edit the boot.ini file on your C-drive partition by adding the following line:

C:\="Microsoft Windows"

Then, shut down and restart Win2K, and you'll have the option to boot either OS.

Dual Applications for Dual Boot
Running a dual-boot system has one more catch: Each OS is on a separate partition and operates unaware of the other, so you need to install applications that you want to use on both OSs twice. Applications can share data and, in most cases, directory structures. Unfortunately, some applications install different executable files for each OS, in which case you have to create separate directory structures. You can't predict which applications will install different executable files, so you need to rely on experience to learn which applications behave this way.

You might also have trouble uninstalling an application that the OSs share. The OS from which you first run the uninstall process will delete the executable files and libraries and will remove entries for the application from the OS's Registry database, but the OS won't touch the other OS's Registry. When you dual-boot to the other OS, the uninstall process might fail because the executable file is missing. Then, you need to reinstall the application before you can uninstall it.

My approach is to install only the applications that I need on each OS. I use Win2K Pro as my primary OS, so it gets applications such as Microsoft Office. I use Win98 mainly for test work, so it gets only the applications that need testing. I need a few applications such as Dynalink Technologies' Clip'nSave on both OSs, and so far both OSs share one copy.

Complicated Setup
Setting up dual-boot applications is more complicated than it has to be. Back in the Windows NT and Windows 3.x days, a much cleaner approach existed—NT Setup automatically assumed it would dual-boot with Windows 3.x, and Windows 3.x applications automatically migrated to the NT Registry whenever NT started. This approach doesn't work with Win2K Pro for technical reasons and because Microsoft believes only a small number of users need to use a dual-boot setup.

I think Microsoft's belief is wrong. I won't abandon Win98 until more hardware and software vendors support Win2K, and I don't think I'm alone. I hope that in the future, Microsoft will base one standard version of Windows on the Win2K kernel. Then, no one will need a dual-boot setup. However, this dream won't be a reality for a long time, considering that Microsoft's Millennium project (a Win98 follow-up) doesn't use the Win2K kernel.