CS614 Lectures and Reading

Note, Solutions to the homework questions (HW) should be written-up and submitted to the instructor by email before the start of class. Don't write a lot and don't use fancy formatting or attachments---use plain ASCII and write just the few paragraphs needed to demonstrate that you have read the listed papers and thought about the question.

Jan 24 [Mon] (Speaker: Schneider)

Jan 26 [Wed] (Speaker: Schneider)

Continuation of Jan 24....

Jan 31 [Mon] (Speaker: DeWitt)

HW: Would each of these authors be comfortable writing their systems using Java? Explain.

Feb 2 [Wed] (Speaker: Brodsky)

HW: What aspects of Hydra are preserved in Mach? What aspects are abandoned?

Feb 7 [Mon] (Speaker: Moczydlowski)

HW: State the fundamentally different philosophies held by micro-kernel and exo-kernel partisans. Give an example of something one might find in a micro-kernel but not in an exo-kernel and vice-versa.

Feb 9 [Wed] (Speaker: Orlovich)

HW: Does the term "domain" mean the same thing in both papers? If not, mention some differences. Also, how does each proposal cope with the reality that I/O devices make transfers to real addresses (and not virtual addresses)?

Feb 14 [Mon] (Speaker Song)

HW: Agree or disagree with the following statement, giving evidence to support your position: "Different motivations drive use of a high-level language in each of these papers."

Feb 16 [Wed] (Speaker: Marian)

HW: UNIX file system implementations involve a level of indirection due to the i-nodes. Does the contribution of each of these papers depend in a significant way on having these i-nodes? How?

Feb 21 [Mon] (Speaker: Orlovich)

HW: What technological trends in the 1990's made log-structured file systems attractive a decade ago, and what technological trends made stackable file systems attractive a decade ago? The technological picture is different in 2005---how are those justifications for these technologies affected as a result?

Feb 23 [Wed] (Speaker: Li)

HW: Could a processor whose memory translation hardware involves both segmentation and paging be used to implement a segmented DSM? If so, would this require running one instance of the DSM protocols for both the segmentation and the paging or two separate instances (one for the segmentation and one for the paging)? Why might supporting segmentation be especially appealing to the MUNIN designers?

Feb 28 [Mon] (Speaker: Brodsky)

HW: In V, an attempt is made to unify groups and individual processes but an individual process remains different from a process group of size one---explain these differences. In Locus, the focus appears to be on files and reliability; what is the failure model being assumed?

Mar 2 [Wed] (Speaker: Marian)

HW: All of these papers discuss RPC implementations, but each paper concentrates on a different aspect of the problem (besides differing in programming language and/or target system). What are these different areas of focus?

Mar 7 [Mon] (Speaker: Lifson)

HW: Each of these three papers describes a file system design and a prototype implementation, but each prototype implements only some parts of the design. For each paper, list the significant pieces of the design omitted from the prototype.

Mar 9 [Wed] (Speaker: Li)

HW: The use of whole-file transfer brought various different benefits over the successive steps of the AFS evolution and then the evolution of CODA. Name each of these steps and, for each, indicate the extend to which whole-file transfer is enabling.

Mar 14 [Mon] (Speaker: Song)

HW: What technological trends are driving the designs in all three of these papers?

Mar 16 [Wed] (Speaker: Johansen)

Mar 21, Mar 23: Spring Break (no class)

Mar 28 [Mon] (Speaker: Schneider)

HW: To be assigned in class.

Mar 30 [Wed] (Speaker: Schneider)

HW: To be assigned in class.

Apr 4 [Mon] (Speaker: DeWitt)

HW: Lamport et al argues the impossibility of an oral messages algorithm for three generals with at most one traitor. Suppose traitors were not Byzantine but instead somewhat restricted in their behavior to "send omission" failures. That is, a traitor follows the algorithm but only a subset of the messages the traitor sends actually reach the receiver. Is agreement still impossible? Give an argument or outline a protocol.

Apr 6 [Wed] (Speaker: Moczydlowski)

HW: None assigned.

Apr 11 [Mon] (Speaker: Birman)

HW: What are the major points of difference between the Birman school and the Cheriton-Skeen school?

Apr 13 [Wed] (Speaker: Li)

HW: To what extent is redundant information stored within a quorum in the schemes found in each paper. Where there is redundancy, what does it buy?

Apr 18 [Mon] (Speaker: Schneider)

HW: We have seen that quorums directly support only read and write operations, yet COCA is able to implement a certificate update operation using quorums. Outline the approach used by COCA for this. Could this same approach be used to implement arbitrary update operations with quorums and thereby support the functionality of replicated state machines? If not, discuss what class of update operations can be accomodated using the approach in COCA.

Apr 20 [Wed] (Speaker: Orlovich)

HW: Consider a program optimizer that is capable of deleting redundant code. So, if a program that already satisfies 'code safety' is input to an SFI insertion tool and the output of that then passed through this program optimizer, the result will be the original program. How might a version of PCC be employed to now remove the SFI insertion tool and the program optimizer from the Trusted Computing Base?

Apr 25 [Mon] (Speaker: Lifson)

HW: The Pastry paper defines a peer-to-peer system as "a distributed system in which all nodes have identical capabilities and responsibilities and all communication is symmetric." To what extent do each of the three papers we discuss today satisfy that definition? Give specific points of agreement and difference for each paper.

Apr 27 [Wed] (Speaker: Mosczydlowski)

HW: For each paper of the three papers, discuss their position on revocation of access. Is some means provided? If not, why? If so, what is it?

May 2 [Mon] (Speaker: Marian)

HW: Are the consistency guarantees being achieved by these two systems identical? In not, briefly explain the differences.

May 4 [Wed] (Speaker: Song)

HW: To preserve your anonymity, instead of submitting your "solution" to this HW by email, please produce a hardcopy (without any identifying markings) and submit that. Write a brief essay, in which you discuss how this course could be improved, perhaps providing a paragraph on each of the following: (i) any papers or topics that should be added (but also say what should be removed to accommodate the additional material); (ii) whether you find the format useful and efficient; (iii) anything else that you found interesting or off-putting about our class and the manner in which it was run.