Reading Questions

The Structure of the "THE" Multiprogramming System
The Nucleus of a Multiprogramming System

1 - What are the main philosophical differences in design of the THE system and the Nucleus system?

A good example of a write-up: here.

HYDRA: The Kernel of a Multiprocessor Operating System

2 - What is the major weakness of the Hydra system? (discuss)

A good example of a write-up: here.

The UNIX Time-Sharing System
Pilot: An Operating System for a Personal Computer

3 - How should the OS for a personal computer (a PC on your desktop) differ from the OS for a minicomputer (a shared machine in the basement)?

A good example of a write-up: here.

Disco: Running Commodity Operating Systems on Scalable Multiprocessors

4 - Other than performance, what is your major criticism of the approach that Disco takes in constructing an operating environment for a shared-memory multiprocessor?

A good example of a write-up: here.

Exterminate All Operating System Abstractions
Exokernel: An Operating System Architecture for Application-level Resource Management

5 - Compare and contrast the philosophy of Exokernel with that of Nucleus.

A good example of a write-up: here.

Stable Storage

A Fast File System for UNIX
The Design and Implementation of a Log-Structured File System

6 - LFS argues that if workloads are write-dominated, LFS is a good idea. If workloads remain read-dominated (say 70% reads, 30% writes), would you still want to use LFS? (why or why not?)

A good example of a write-up: here.

Deciding When to Forget in the Elephant File System

7 - How would you build Elephant on top of LFS? (just include a brief discussion of LFS data structures and mechanisms that would need to change).

A good example of a write-up: here.

A Case for Redundant Arrays of Inexpensive Disks (RAID)

8 - Assume you have a RAID-5 array. Which file system would you choose to use with it, FFS or LFS? Why?

A good example of a write-up: here.

Scheduling and Resource Management

Lottery Scheduling: Flexible Proportional-Share Resource Management
Resource Containers: A New Facility for Resource Management in Server Systems

9 - Which parts of the lottery scheduling system are mechanism, and which are policy? Which parts of the resource container system are mechanism, and which are policy?

A good example of a write-up: here.

Scheduler Activations: Effective Kernel Support for the User-Level Management of Parallelism

10 - Discuss a system that tries to utilize lottery scheduling, resource containers, and scheduler activations (this can be done simply by describing a scenario where a few jobs are active). Are these techniques all complementary?

A good example of a write-up: here.

Memory Management

Virtual Memory Management in the VAX/VMS Operating System
The Duality of Memory and Communication in the Implementation of a Multiprocessor Operating System

11 - As compared to traditional memory management systems such as the one described in the VAX/VMS paper, Mach provides a higher degree of flexibility to applications. Discuss two potential negatives of such flexibility.

Virtual Memory, Processes, and Sharing in MULTICS

12 - Where in the Unix operating system do you see influence from MULTICS? (name and discuss at least two items)

Interprocess Communication and Networking

Implementing Remote Procedure Calls
U-Net: A User-Level Network Interface for Parallel and Distributed Computing

13 - Describe how you would build RPC on top of U-net. As the
implementor of the RPC package, what functionality would like from U-net that
is not present?

Distributed Systems

Due by class on 11/07

A Comparison of Two Distributed Systems: Amoeba and Sprite
Cluster-Based Scalable Network Services

14 - Let's say you are building a system similar to that described in the cluster-based scalable services paper. Name and discuss three features you would like to have provided by a distributed operating system.

Distributed Stable Storage

Design and Implementation of the Sun Network Filesystem
Scale and Performance in a Distributed File System

15 - Compare the protocols of AFS and NFS to HTTP. Discuss similarities and differences in terms of performance, consistency, and crash recovery.

Measurements of a Distributed File System

16 - Name two trends in this paper that seem like they will continue. Name two that seem unlikely to do so. Discuss.


Disconnected Operation in the Coda File System
Managing Update Conflicts in Bayou, a Weakly Connected Replicated Storage System

17 - Compare Coda and Bayou. What is the main advantage of a system like Coda? What is the main advantage of a system like Bayou?


Data Security
Using Encryption for Authentication in Large Networks of Computers

18 - Last one! Discuss denial of service attacks (such as the one that shutdown Yahoo last year) and methods that could be used to prevent them from occuring.