Definition
Plain language
A Linux tool that takes a snapshot of a running program so you can pause it and bring it back later.
As stated in the literature
Checkpoint/Restore In Userspace, a Linux facility that serializes a running process tree (memory, file descriptors, sockets) to disk for later restoration, used as the durability path in DeltaBox-style checkpointing.
Also called: Checkpoint/Restore In Userspace
Why it matters: It enables checkpoint/restore for arbitrary Linux processes, which is the foundation for fast snapshotting in agent sandboxes and migration in cloud systems.
For example, CRIU dumps a running database process to disk, the machine is rebooted, and the database resumes mid-query as if nothing happened.
Heard on the show
“The existing tools that do this — Docker commits, Firecracker VM snapshots, CRIU process checkpointing — they all duplicate the whole state.”Episode 068 — The OS Trick That Makes Tree Search Practical for Coding Agents