On June 25th, Microsoft released Windows 98 to the general public. Though it promises better ease-of-use through Internet Explorer's shell integration and better internet connectivity, the core of the OS remains the same as Windows 95 OSR 2.1. But the question is, has disk performance been impacted?
Windows 98 includes an Application Start Tracker that logs the order in which various files are loaded by the system during bootup and the launching of programs. When Win98 users defragment their hard drives, the start log is consulted and some fragmentation is purposefully induced to minimize seeking during bootup and program launches. While this may be quite noticeable in actual use, such a performance increase shouldn't be reflected in WinBench 98 or Threadmark since test files are created and trials are run all in one swoop withoutany defragmentation/optimization being performed in the interim.
Also included in the new release are some fixes and patches that were previously required by Windows 95 to ensure maximum DMA mode compatibility, specifically REMIDEUP.EXE and SETUP_EX.EXE (the 82371 update). Primarily intended to address ATA removable storage and newer Intel Chipsets, these files also allowed smoother access of DMA using OSR2's native drivers. Windows 98, of course, has all this built-in already. ATA busmastering continues to mature.