For user-mode emulation QEMU maps emulated threads to host threads. Hardware virtualization is not the same as hardware emulation. Instead backward compatibility was achieved using software emulation. KVM provides device abstraction but no processor emulation. The operating systems the archivers can run on without emulation or compatibility layer. However, it retains the "Graphics Synthesizer" GPU resulting in a hybrid hardware and software emulation. It is designed to run well under virtualization or x86 emulation. Not all SNES games can work due to missing emulation of custom cartridge chipsets. This is what distinguishes a VMM from the more general class of hardware emulation software. No code emulation or virtualization occurs when running a Windows application under Wine. Compatibility features included emulation for 7070/7074, 7080, and 709/7090/7094/7094 II. From the 1980s, teleprinters were replaced by computers running teleprinter emulation software. This will provide access to an emulation of a standard 101/102-key keyboard. Windows/386 2.1 had a protected mode kernel with LIM-standard EMS emulation. The current mode of operation is stored in the emulation (E) bit.