At the very beginning, google released google android SDK, it is running on the emulator. There is no hardware.
The Google android emulator is included in the google android sdk. So far google provides three platforms sdk, they are windows, Mac OS X (intel), Linux (i386). The emulator is in the tools folder: emulator.
The google android emulator is based on the qemu, which is a open source. Google makes some changes based on the qemu 0.8.2. The source code is also available. With the emulator source, you can make any changes you want, and replace the original one to look for information you want. One command to compile the emulator source code: build-emulator.sh