Hacker News on 21 July 2020

• Systems Design for Advanced Beginners
• Invert, always, invert
• Essays on programming I think about a lot
• India, Jio, and the Four Internets
• Terry Tao on some desirable properties of mathematical notation
• How you 'attach' to people may explain a lot about your inner life
• Monitoring your own infrastructure using Grafana, InfluxDB, and CollectD
• Wiki.js
• Harvard CS professor David Malan built a distance-learning empire
• The Billionaire Behind Efforts to Kill the U.S. Postal Service [pdf]