The tape's receipt

what the collector caught, session by session

SPX: session running, the measured book was last written 1 s ago.
Other symbols: 123 of 124 option-chain books built in the last 20 minutes, newest at 2026-10-12 13:15 ET.

Every session in the archive is rebuilt from the SPXW options tape as it prints. This page says how much of each day arrived: the minutes the payload carries against a full session, the seconds that carry a print, the packets the gateway reported dropped, the engine restarts and the replay that follows one, and the minute the finished day was published to the store. The numbers come from the collector's own logs and the payload itself; nothing here is estimated.

Last 60 sessions: 60 complete; over the 35 with a log, 1.59 billion dropped packets and 36 engine restarts, every restart replayed from the tape. Drops and restarts are recorded from 2026-08-24; earlier days carry the payload's own count only.

How to read it

• Tape. Minutes in the payload against 390 (a full session; an early close counts its own length). Under 100% on a finished day means the collector missed part of it and the day was not rebuilt from history.
• Dropped packets. The gateway's own "SLOW CONSUMER" count: prints the feed discarded because the reader fell behind. Zero is the normal reading.
• Engine restarts. The live engine died and was restarted by its supervisor; on restart it replays the day's prints from the tape before resuming, so the book after a restart equals the book a batch rebuild would produce.
• Published. When the finished day reached the store. The files a DATASET licence delivers leave minutes later.

Updated after every archive pass, about every five minutes while a day is shipping. The same data is at /snapshots/receipts.json.