JMCE a multiple computer emulator, a simulator for 8-bit microprocessors (Intel 8080, Zilog Z80, Intel 8051, etc.) and for many of the computers based over them, such as ZX Spectrum, Altair 8800, and Z80Pack, running their original ROM and operating system. All JMCE computers can be configured programmatically or using XML. For example, it is possible connect the console of a simulated IMSAI 8080 to one TCP server or to one physical serial interface without writing even one line of code. It is also possible to change the memory for the Z80Pack computer from plain to banked memory only by editing a single XML file.