OS9 Helper allows you to install 9.2.1 or 9.2.2 on certain 'Old World' Macs that Apple has decided to drop support for. OS 9.1 is the final version that Apple allows to install on anything previous to the Beige G3. Apple touted 9.2.1 as a minor update to 9.1 that added 'better classic compatibility'. However, the performance inprovements that were added in 9.2.x are clearly noticeable once you install it. In particular, the Finder is incredibly responsive, and Open Transport networking is vastly more stable. However, the four most important reasons for installing 9.2.x are: Compatibility with ATI's latest drivers. ATI dropped support for OpenGL versions lower than 1.2.2. (9.1 has 1.2.1). You can't run DVD Studio Pro 1.5 or 1.2.1 without 9.2.2. You can't run Final Cut Pro 3 without 9.2.2. Full compatibility with first and second generation iPods.
Mac OS Classic
||Mac OS 9.1