This is highly confusing. For one, it's pretty out of date (tape as "tertiary storage"? 512 byte page size? the whole topic of concurrency control without one m

This is highly confusing. For one, it's pretty out of date (tape as "tertiary storage"? 512 byte page size? the whole topic of concurrency control without one mention of MVCC?), but also, the actual explanation seems to mix up quite a few things. For example: a "Write-Read Conflict" ist just that, a conflict, which a database in some appropriate isolation mode would handle by appropriate locking in order to avoid "reading uncommitted data" (if the transactions were to happen concurrently--per the definition given, operations don't need to happen in concurrent transactions for them to be in conflict). Or, an actual DBMS with MVCC with SSI, like a modern Postgres, would simply execute the read on its snapshot and thus force the reading transaction to precede the writing transaction in any equivalent serialized order (even though the read happened after the write in realtime), and only abort the transaction if that could lead to contradictions (cycles) in the dependency graph.