Episode 5 of the Drill Bits column, which describes the design of a crash-tolerance mechanism for the GDBM database, will be available later in September 2021.

While waiting for episode 5, check out previous installments of Drill Bits:
Efficient Graph Search
Decentralized Computing
Clearing Combinatorial Auctions
Schrodinger's Code: Undefined Behavior in Theory and Practice

You may contact the author at
tpkelly @ { acm.org, cs.princeton.edu, eecs.umich.edu }