Callus is an arcade game emulator written by Bloodlust Software.
Callus allows you to play most Capcom CPS arcade games on your computer. Callus supports most of the CPS1 games, but not all of them because of some encryption issues. One of the best things about Callus is that it is very fast, most games will be full speed on a Pentium 100. While the equivalent games on the MAME emulator take about twice as much CPU to play full speed.
Today, Callus has been completely swallowed up by MAME,but it still performs better on slower processors. Making it an excellent choice for those of you that have early pentium processors. This is also an excellent emulator to use if you are building an arcade emulation cabinet, and only have an older computer to do the emulation duties. A simple Pentium 100 computer, and I-Pac encoder, a few joysticks and the Callus emulator adds up to a very cheap multi-game cabinet.