SoftPC and SoftWindows were software emulators of x86 hardware. The emulators were developed by Insignia Solutions. Available originally on UNIX workstations to run MS-DOS, the software eventually was ported to the classic Mac OS and also gained the ability to run Windows software. Besides Mac OS, supported platforms included SGI IRIX, Sun Solaris, HP-UX, IBM AIX, NeXT, Motorola 88000, DEC VAX/VMS, DEC ULTRIX, and others.
Bundles of SoftPC with Windows (3.x, 95, 98) were called SoftWindows, although it was possible to install Windows into the basic SoftPC environment along with some special utilities provided by Insignia to achieve the same effect.
Beginning in 1996, Insignia commanded the niche for this product area, but it soon faced heavy competition from Connectix with their Virtual PC product. Insignia sold the product line to FWB Software in October 1999 in order to focus on supplying implementations of Java for the mobile device market. FWB continued to sell SoftWindows until March 2001. FWB Software also marketed a separate version of the software that did not include a bundled copy of Windows, called RealPC, until 2003.
When Microsoft released Windows NT it included a subsystem ("WOW" - Windows on Windows, later NTVDM) for running virtualized 16-bit Windows (x86) programs. However, they had also made changes to Windows to allow it to run on alternative processors (Alpha, PowerPC), and for these an emulation layer was needed for programs compiled for Intel processors. Customized versions of Insignia's core emulation system were produced to this end, however the alternative NT architectures never became widely used.
Unlike most emulators, the SoftWindows product used recompiled Windows components to improve performance in most business applications, providing almost native performance (but this meant that, unlike SoftPC, SoftWindows was not upgradable)