Definition
Plain language
A storage area that lives in the computer's fast memory instead of on a disk, so reading and writing to it is extremely quick.
As stated in the literature
A RAM-backed Linux filesystem; used in DeltaCR to hold incremental CRIU process-memory dumps at high speed for low-latency checkpointing.
Why it matters: It provides extremely fast temporary storage by living in memory, which makes operations like rapid checkpointing low-latency.
For example, saving a file to a tmpfs folder writes it straight into the computer's fast memory, so it's read back almost instantly.
Heard on the show
“It starts a CRIU dump in the background — writing only the memory pages that changed since the last checkpoint, to fast tmpfs — and simultaneously, it forks the agent.”Episode 068 — The OS Trick That Makes Tree Search Practical for Coding Agents