Windows 98 Disk Defrag Simulator (defrag98.com)- Windows 98 (Wikipedia)
Windows 98 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. It is the second operating system in the 9x line, as the successor to Windows 95. It was released to manufacturing on May 15, 1998, and generally to retail on June 25, 1998. Like its predecessor, it is a hybrid 16-bit and 32-bit monolithic product with the boot stage based on MS-DOS.