Read the documentation in qemu-doc.html. Fabrice Bellard. To run RECORD/REPLAY, follow the following steps: 1. Configure and compile qemu source, cd qemu-0.13.0-rr && ./myconfigure && make clean && make 2. Create a qcow2 image for guest OS(say image.qcow2). 3. To run in RECORD mode, ./x86_64-softmmu/qemu-system-x86_64 -record filename[name of the record file] image.qcow2 4. To REPLAY the recorded sequence, ./x86_64-softmmu/qemu-system-x86_64 -replay filename[name of the record file] image.qcow2 Good luck! and please let me know about how you used this implementation. thanks, Piyus Kedia (piyus.kedia@cse.iitd.ernet.in)