EROS and a few others snapshot the entire system state. Orthogonal persistence means that applications do not need to take any special action to be a consistent part of the snapshot. The EROS unix emulator, for example, runs unmodified unix binaries. When EROS performs a checkpoint, these programs are checkpointed without their ever being aware that a snapshot was taken. Perhaps more important, no special action is needed by these applications to recover if the system fails.
EROS persistence is a kernel service.
Novell, it seems, had been bragging in their advertisements about their recovery speed. Novell is not is stupid. Somehow, the story of the challenge got around the exhibition floor, and a crowd assembled. Perhaps it was gremlins. Never eager to pass up an opportunity, the keykos staff happily spent the next hour kicking their plug out of the wall.