No questions this week. Work on your projects!
Some questions to think about:
12/1: What aspects of the interface of PAST simplified its implementation, particularly with regard to the distributed systems aspects of PAST?
12/3: Can you find any weaknesses in the authentication protocols in this paper?
Only one question this week (for Wednesday's reading). Work on your projects! (and read the papers)
But, here are some questions to think about:
Coda (don't write this one up, just think about and/or discuss it)
11/17: Why is it hard to automate hoarding (i.e., build a system that did not require users to input a hoard database of some sort) ?
BAD-FS (this is the one writeup you have to do this week)
11/19: Point out three weaknesses in this paper that you think should be addressed by the authors -- be original! Do not simply point out things the authors already have admitted are problems.
Measurements of a DFS (don't write this one up, just think about and/or discuss it)
11/21: Given a trace of file accesses over a given day, how can one calculate file lifetime? What are some possible inaccuracies that could evolve?
No questions this week -- work on your projects! (and read the papers)
Some have suggested that I post a question for discussion. So here it is: Compare and contrast NFS and AFS -- what are the main technical differences between the two?
10/27: Multics is the root of all good ideas in modern computer systems, or so some say. Name and describe two good ideas that you see in the Multics design that have influenced modern computer systems.
10/29: The designers of RPC make a number of design assumptions. List and discuss three of those decisions; did they make good trade-offs in the design?
Comparison of Distributed Systems
10/31: Distributed operating systems like Amoeba and Sprite seem like a cool idea. Why aren't distributed operating systems used today? (your thoughts)
10/22: VMS as described in this paper does not use LRU. Describe the scheme they use, why they use it, and how it might be worse than pure LRU based page management.
10/24 (moved to 10/27): Multics is the root of all good ideas in modern computer systems, or so some say. Name and describe two good ideas that you see in the Multics design that have influenced modern computer systems.
10/13: Come up with a deterministic version of lottery scheduling. How does it compare to the randomized version as described in the paper?
10/15: Criticize resource containers. What are its major flaws?
10/17: Evaluate the performance evaluation in this paper: what does it show? What is missing? Does it make the points that the paper should make? (be specific)
Monitors and Mesa
10/10: In theory, there's no difference between theory and practice, but in practice, there is. Discuss how the "practice" as described in the Mesa paper differs from the "theory" described in the Monitors paper. Be critical.
10/1 (Wednesday): Anticipatory scheduling teaches us that waiting can speed things up. Think up and describe two or three other examples in computer systems where waiting can speed things up.
10/3 (Friday): Assume you have a RAID-5 array. Which file system would you choose to use with it, FFS or LFS? Justify.
9/26 (for Friday/Monday) I/O Lite, while technically interesting, is not available in modern kernels. Discuss why this might be, focusing on technical reasons for the lack of adoption.
9/24: (for Wednesday)
LFS argues that if workloads are write-dominated, LFS is a good idea. If workloads remain read-dominated (say 80% reads, 20% writes), would you still want to use LFS? (why or why not?)
FFS is an old system, with old assumptions about disk technology. What assumptions made by FFS (either in expected workload or in disk technology) have changed? Is the design of FFS less relevant today than it was years ago?
Criticize the gray-box approach. Where is it likely to break down? What kinds of OS services can you really implement at user-level? etc.
Discuss the main differences between resource management in a typical "monolithic" OS and the Disco virtual machine monitor.
Compare and contrast the philosophy of Exokernel with that of Nucleus.
HYDRA: The Kernel of a Multiprocessor Operating System
Hydra purports in many ways to be a minimal system, ala Nucleus. In what ways is Hydra similar to Nucleus, and in what ways is it different?
The Structure of the "THE" Multiprogramming System
The Nucleus of a Multiprogramming System
What are the main philosophical differences in design of the THE system and the Nucleus system?