HotOS-IIV Review

Naomaru Itoi
itoi@eecs.umich.edu

Session 1: File Systems

``Elephant: The File System That Never Forgets''
Santry, D.J., Feeley, M.J., Hutchinson, N.C., Veitch, A.C.

A filesystem that stores old versions of files and directories, even if they are already removed by a user. They do that by mapping a file to a set of inodes which represent different versions of inodes in a chronological order.

I think it is a very interesting paper because user faults occur very often, but I have not seen many reliability related papers addressing them. I would love to use it if I will be free from pressure of being careful removing files.

``Caching Documents with Active Properties''
de Lara, E., Petersen, K., Terry, D.B., LaMarca, A., Thornton, J., Salisbury, M., Dourish, P., Edwards, K., Lamping, J.

Filesystem extension to store a property in a file to invoke Java programs dynamically. For example, ``send-copy-to'' property sends a copy of a document whenever it is saved, ``translate-to-french'' property translates an English document whenever it is saved, etc.

``The Case for Adaptive File Access Pattern Modeling''
Kroeger, T.M., Long, D.D.E

Finite Multi-Order Context Modeling (FMOC) is a good file access pattern prediction model, but takes too much space. They minimize its space requirement while keeping its accuracy.

Session 2: Great Expectations

``ISTORE: Introspective Storage for Data-Intensive Network Services''
Brown, A., Oppenheimer, D., Keeton, K., Thomas, R., Kubiatowicz, J., Patterson, D.A.

Position paper for a clustered servers to provide maintainability, availability, scalability, performance, and cost.

``OS Support for General-Purpose Routers''
Peterson, L.L., Karlin, S.C., Li, K.

Position paper for extensible routers with off-the-shelf HW and OSs.

``Conductor: A Framework for Distributed Adaptation''
Yarvis, M., Reiher, P., Popek, G.J.

Position paper for multiple proxies to provide adaptation (service degradation).

Session 3: Networking

``An End-System Architecture for Unified Congestion Management''
Rahul, H.S., Balakrishnan, H., Seshan, S.

Position paper for a kernel embedded congestion manager. All applications talks to the congestion manager before establishing a TCP connection, and learn about network state.

``The Case for Informed Transport Protocols''
Savage, S., Cardwell, N., Anderson, T.

No summary.

``Transparent Communication Management in Wireless Networks''
Kidston, D., Black, J.P., Kunz, T.

No summary.

Session 4-1: PANEL: LIES, DAMN LIES & BENCHMARKS

``Brittle metrics in operating systems research''
Mogul, J.C.

Many operating system research papers use unrealistic benchmarks (often too simple).

``The Problems You're Having May Not Be the Problems You Think You're Having: Results from a Latency Study of Windows NT''
Jones, M.B., Regehr, J.

Extremely interesting paper.

Section 4.1 presents Windows NT multimedia clock's weird behavior. When the clock frequency is set to fire a callback every 1ms, it sleeps for 2 ms, fires two callbacks continuously, sleeps 2 ms, fires two, ... repeats.

Section 4.4 presents mysterious delay caused by ethernet cards. DEC dc21x4 PCI Ethernet Card polls the ethernet device every 5 seconds, and it causes 6 - 7 ms delay. Also, Intel EtherExpress 16 ISA Ethernet Card resets itself every 10 seconds, and it takes 17 ms.

Section 4.5 presents some video cards optimized for a specific benchmark (WinBench Graphics WinMark), sacrificing user performance. When the card's command FIFO is full (because of a drag-and-drop, etc.), it stalls a whole computer for 25 - 30 ms.

``The Case for Application-Specific Benchmarking''
Seltzer, M., Krinsky, D., Smith, K., Zhang, C.

Make a vector to represent application's resource requirement (CPU, memory, I/O, network, etc.) and another vector to represent a computer's resource power obtained by microbenchmarks. Take a dot-product of them, and that predicts how well the computer handles the application.

Session 4-2: PANEL: THE THIN RED LINE

``Intra-Address Space Protection Using Segmentation Hardware''
Chiueh, T., Venkitachalam, G., Pradhan, P.

Take advantage of x86 hardware (segmentation) to isolate applications' address spaces.

``Drawing the Red Line in Java''
Back, G., Hsieh, W.

Because JVM runs multiple applications, it needs a user/kernel boundary.

``Hey, You Got Your Language In My Operating System!''
Howell, J., Montague, M.

Something like SPIN?

Session 5: POTPOURRI

``The Case for Higher-Level Power Management''
Ellis, C.S.

A mobile computer needs an application specific power management system, e.g., an application should tell an underlying OS that it can turn off the display when it is downloading bulk data, etc.