Wikipedia
PCem
PCem (short for PC Emulator) is a virtualization software and IBM PC emulator for Windows and Linux that specializes in running old operating systems and software that are designed for IBM PC compatibles. Originally developed as an IBM PC XT emulator, it later emulates other IBM PC compatible computers as well.
The current version of PCem is PCem v11, released on June 5, 2016. Unofficial builds of PCem are also available, such as PCem-X and PCem-unofficial, which includes a number of enhanced features. Versions of PCem from v0.5 until v8 are not available for download, due to the number of bugs that aren't fixed in those versions.