Exercise 6: Wednesday 8.12. or Thursday 9.12. or Friday 10.12

Note that Monday's exercise session is cancelled due to it overlapping with the local Independence day. Alternative dates for the 6. exercise session are as follows:

• Wednesday 8.12. at 12-14 in room B119
• Thursday 9.12. at 16-18 in room C222
• Friday 10.12. at 12-14 in room B119

Background materials: see the lecture slides for the consistency types

1. For each of the 8 data-centric consistency types, construct a sequence of events which is illegal. Be prepared to present exactly why your sequence is illegal. Emphasis on this task is on the presentation. Follow the notation given by the slides. The 8 types are:

strict, linearizability sequential, causal, FIFO, weak, release, and entry

2. Maintaining consistency in a distributed system is of some importance. Give two examples each of embarassing occurrencies of lacking consistency, which
are related to data updates, replicates, caching, server failures,  clocks, and user interfaces (consistency of keyboard and screen). For example, the occurencies may conside using the WWW, updating a name-service database, or something else.