JSIM51 is a powerful 8051 controller simulator and HLL-debugger. JSIM can load absolute files in OMF-51 format or the extended OMF-51 format, which is used by the Keil-C-Compiler. It lets you test software parts independently of the target platform. The speed of this simulator on a Pentium 200, reaches nearly that of an 8051 clocked with 10MHz (in the best case without trace). The operation philosophy and user interface is designed to be similar to that of Microsoft's VisualC++ 4.2.