Smolvm – MicroVMs with CRIU Functionality

Smolvm, from smol machines, aims to give an AI agent an undo button for its whole virtual computer. Its engineering post says a checkpoint saves memory, CPU state, running processes and disks together, so files and processes stay consistent after a restore. Restoring creates a new machine from the checkpoint, each checkpoint records its parent, and rewinding to an older point lets new work branch instead of overwriting history.

Branching forks a running machine into copy-on-write children that each store only their own changes. The post's timings are examples: checkpointing a small Alpine Linux machine on a MacBook took 2.7 seconds with a 71 millisecond pause, and branching a 1 GiB machine paused the source for about 80 milliseconds. Restores need the same operating system and CPU architecture, history keeps 32 points by default, and Windows hosts are not supported yet. The post contrasts itself with Firecracker, the microVM technology that Perplexity described using for its sandboxes, saying Firecracker does not save disks but captures frequent snapshots more cheaply.