A DOS attack is not a DoS attack
Anyone who works in an IT related field, or who possesses a basic understanding of networking, or even those who have used the internet in the past 10 years, have heard of DoS attacks. Regardless of method, the concept of bombarding a server with data to the point of failure is a simple concept.
Historically, this started with hackers crashing web servers with an onslaught of request packets. The cat and mouse game of security developments vs. hacking attacks, generated a wide variety of DoS and subsequent Distributed DoS (DDoS) weaponry. Servers could be pinged to death, flooded with SYNs, overwhelmed by fragmented packet reassembly or defeated by DNS amplification. Armed with large botnets, today's attacks include powerful variations and combinations of these, having lead to shutdowns of many large sites, as well as crippling the country of Estonia.