You can use MSI files to deploy customized applications and service packs to workstations on your network. The problem is that MSI files require a special installer. Windows XP and Windows 2000 Professional both come with an MSI installer, but older versions of Windows don’t. Here’s how you can deploy MSI packages to Windows 9.x workstations.

What’s an MSI file?
MSI is short for Microsoft System Installer. MSI files are installation packages somewhat akin to ZIP files. MSI files contain all of the information necessary to install an application, including the registry changes needed to be made on a workstation. When you distribute an application, rather than copying multiple files, you just copy one large one.

Microsoft first created MSI files in conjunction with the Microsoft Installer to help ease the pain of DLL hell. Regular setup programs can overwrite system DLLs or install a version of a DLL that duplicates, but is incompatible, with a version previously installed by another application. The Microsoft Installer, in conjunction with an MSI package, helps prevent this from happening.

Although you can create MSI files of your own using products like WinInstallLE, normally you’ll only find MSI files from software vendors. Microsoft likes to use MSI files to distribute applications and service packs for products like Microsoft Office. Using tools in the Microsoft Office Resource Kit, you can create custom MSI files to install all or part of Microsoft Office to make sure that program configurations are consistent throughout the enterprise.

The Microsoft Installer first appeared with Windows 2000. Microsoft updated it to version 2.0 with Windows XP. If you’re using an older version of Windows, like Windows 98 or Windows ME, in your organization, then MSI files won’t work by default. Windows 9x won’t know what to do with them. Fortunately, Microsoft has created a version of the Microsoft Installer 2.0 for Windows 9.x.

Obtaining and installing the Microsoft Installer
You can obtain the Microsoft Windows Installer 2.0 for Windows 9x from Microsoft’s Download Center. The file you’ll want, InstMsiA.exe, is only 1.7 MB in size, so it should download very quickly. You can either save the file to your workstation or open it from the Web site.

There are no gotchas when installing the Installer. When you run InstMsiA.exe, it automatically updates your Windows 9x workstation. When you reboot the workstation, it makes a few additional modifications, but that’s essentially it. Once you’ve installed it, there’s no way to remove it. It runs as a built-in service for Windows 98.