The whole 8051 emulator industry relies on MetaLink patented technologies. MetaLink patents and technologies have been licensed to many major semiconductor companies including, Analog Devices, Atmel, Dallas Semiconductor, Hynix, Infineon, NXP (Philips) and SST. 
In addition, every major 8051 emulator manufacturer must license MetaLink's technology to produce their own 8051 emulators when using this technology.