Scalability

1. Explain the significance of Amdahl’s law for scalability.
2. Which sources of execution time jitter can cause delays in HPC applications?
3. What strategies can be applied to reduce or mitigate such jitter?

DNS

4. What is an Internet Standard, and which document defines the DNS protocol?
5. Which design strategies enable the DNS to scale?
6. Demonstrate the interaction of the resolver library with the DNS servers.
   • Using dig, manually replay all name-server requests emitted by the resolver library and its primary name server when searching for an A record for the name unknown.tu-dresden.de.
   • Hint: Use the dig option +norecurse to replay search steps individually.
   • Did one of the DNS answers come from a name server's cache? If yes: How would the request-answer sequence have differed if all of the participating name server's caches would have been empty?
7. Besides translating names to IP addresses, which other information is stored in DNS?