colloquiums summaries

CS COLLOQUIUM
End-to-End Quality of Service for Large Distributed Storage
Carlos G. Maltzahn
Research Faculty
University of California, Santa Cruz
Tuesday, October 16, 2007
Hosted by Dirk Grunwald

Large distributed systems usually have large and complex storage systems, which are very hard to manage. One particular challenge is ensuring that applications using those systems get good predictable performance.

Carlos—a former CU PhD Student—gave an overview of a project that he is working on to address the issue of end-to-end quality of service for large distributed storage. In his talk he focused and spent a lot of time on I/O scheduling, where he introduced “Fahrrad” a universal real-time disk scheduler. Fahrrad is the German word for bicycle, the name was chosen as Carlos and his colleague are German and they thought that it would be a good name to reflect the improvement that the new scheduler introduces.
Carlos started the talk by giving a brief introduction to how the most operating systems schedulers operate. He pointed out how most schedulers use over-provisioning to handle mixed workloads, and how Fahrrad can have significant improvement over traditional schedulers. Carlos then explained some of the basic principles that the Fahrrad scheduler follow.

Although the talk was interesting, the fact that their paper was not published yet prevented Carlos from answering several questions, which would have explained several ambiguous ideas.

CS COLLOQUIUM
Recent Progress in Cryptographic Hashing
John R. Black
Department of Computer Science
University of Colorado at Boulder
Thursday, October 18, 2007

Computer and information security is one of the fields that is continuously gaining importance and popularity, especially with the increased popularity of the internet an online business. And at the heart of information security is Cryptology. Cryptology is typically defined as cryptography (the construction of cryptographic algorithms) and cryptanalysis (attacks on these algorithms). Cryptographic hash functions are one of the core building blocks within both security protocols and other application domains.

In his talk Prof. Black gave a very useful fun and interesting overview of network security in general and Cryptographic algorithms in specific. One thing that I found very interesting is the story of how MD5—a well known message digest algorithm—was broken in 2004 by Xiooyun Wang the professor from China, and how it used to require a super computer and few days to break the algorithm and then by introducing new methods the task can be done on a home PC in less than a minute.

Another thing I liked about the talk is how things were explained and related to everyone who is not very familiar with cryptography and security. For example many of us were not sure what is the effect of breaking the MD5 algorithm. Prof. Black explained that since MD5 is widely used to check for message integrity, it is now possible for some hacker to change or modify the content of a message in a way that is undetectable.

All in all, I really enjoyed the talk and learned some very interesting facts.

Last modified 24 November 2007 at 7:48 pm by mohammad