Hard things in Computer Science

The article challenges the common quote that only two things are hard in computer science—cache invalidation and naming things—by highlighting several additional difficult areas. It explains the complexities of cache invalidation, particularly balancing stale data and unnecessary reloads through TTL settings, and emphasizes the importance and difficulty of precise naming in code to avoid misunderstandings. Other hard problems discussed include handling dates, times, and timezones; accurately estimating software projects; and managing the inherent challenges in distributed systems such as dual writes and leader election. Overall, it argues that many aspects of computer science are challenging beyond the traditional quote.