Exploiting weak connectivity for mobile file access

Mummert, Lily B.; Ebling, Maria R.; Satyanarayanan, Mahadev

doi:10.1145/224056.224068

Cited by 137 publications

(60 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…To generate the initial access distribution, we replayed a trace of distributed file system accesses using Mummert's DFSTrace tool [18]. This tool re-executes previously recorded file system operations such as open and mkdir, preserving the inter-arrival time of each system call.…”

Section: Methodsmentioning

confidence: 99%

“…For example, the Coda distributed file system prefetches file data from servers to improve performance and guard against disconnection [12]. Coda also writes file modifications back to the server asynchronously [18]. For both prefetching and asynchronous writes, latency is not a critical constraint since a human user is not waiting for the transfer to complete.…”

Section: Respect the Critical Pathmentioning

confidence: 99%

See 1 more Smart Citation

Self-Tuning Wireless Network Power Management

2005

View full text Add to dashboard Cite

Current wireless network power management often substantially degrades performance and may even increase overall energy usage when used with latency-sensitive applications. We propose self-tuning power management (STPM) that adapts its behavior to the access patterns and intent of applications, the characteristics of the network interface, and the energy usage of the platform. We have implemented STPM as a Linux kernel module-our results show substantial benefits for distributed file systems, streaming audio, and thinclient applications. Compared to default 802.11b power management, STPM reduces the total energy usage of an iPAQ running the Coda distributed file system by 21% while also reducing interactive file system delay by 80%. Further, STPM adapts to diverse operating conditions: it yields good results on both laptops and handhelds, supports 802.11b network interfaces with substantially different characteristics, and performs well across a range of application network access patterns.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Respect the Critical Pathmentioning

confidence: 99%

Self-Tuning Wireless Network Power Management

2005

View full text Add to dashboard Cite

show abstract

“…The priority aging in [20], for instance, continually depresses a job's priority until the end of every decay cycle. The aging window in [21] is the amount of time a record is eligible for reintegration. Comparing to our approaches, most of them simply keep track of time then take some actions such as update, remove or reuse the data in certain time points.…”

Section: Related Workmentioning

confidence: 99%

Delay reduction techniques for playout buffering

Sreenan

Chen²,

Agrawal³

et al. 2000

IEEE Trans. Multimedia

View full text Add to dashboard Cite

Receiver synchronization of continuous media streams is required to deal with delay differences and variations resulting from delivery over packet networks such as the Internet. This function is commonly provided using per-stream playout buffers which introduce additional delay in order to produce a playout schedule which meets the synchronization requirements. Packets which arrive after their scheduled playout time are considered late and are discarded. In this paper, we present the Concord algorithm, which provides a delay-sensitive solution for playout buffering. It records historical information and uses it to make short-term predictions about network delay with the aim of not reacting too quickly to short-lived delay variations. This allows an application-controlled tradeoff of packet lateness against buffering delay, suitable for applications which demand low delay but can tolerate or conceal a small amount of late packets. We present a selection of results from an extensive evaluation of Concord using Internet traffic traces. We explore the use of aging techniques to improve the effectiveness of the historical information and hence, the delay predictions. The results show that Concord can produce significant reductions in buffering delay and delay variations at the expense of packet lateness values of less than 1%.Index Terms-Multimedia stream synchronization, playout buffering.

show abstract

“…Supporting file accesses in a mobile environment in the presence of weak connectivity has been introduced in later versions of Coda through the introduction of a new 'write disconnected' state of operation (Mummert et al, 1995). Coda is focused on file accesses rather than accesses to database items.…”

Section: Related Workmentioning

confidence: 99%

Incremental View Maintenance for Mobile Databases

Lee

Leong

2000

Knowledge and Information Systems

View full text Add to dashboard Cite

In a mobile environment, querying a database at a stationary server from a mobile client is expensive due to the limited bandwidth of a wireless channel and the instability of the wireless network. We address this problem by maintaining a materialized view in a mobile client's local storage. Such a materialized view can be considered as a data warehouse. The materialized view contains results of common queries in which the mobile client is interested. In this paper, we address the view update problem for maintaining the consistency between a materialized view at a mobile client and the database server. The content of a materialized view could become incoherent with that at the database server when the content of the database server and/or when the location of the client is changed. Existing view update mechanisms are 'push-based'. The server is responsible for notifying all clients whose views might be affected by the changes in database or the mobility of the client. This is not appropriate in a mobile environment due to the frequent wireless channel disconnection. Furthermore, it is not easy for a server to keep track of client movements to update individual client location-dependent views. We propose a 'pull-based' approach that allows a materialized view to be updated at a client in an incremental manner, requiring a client to request changes to its view from the server. We demonstrate the feasibility of our approach with experimental results.

show abstract

Exploiting weak connectivity for mobile file access

Cited by 137 publications

References 19 publications

Self-Tuning Wireless Network Power Management

Self-Tuning Wireless Network Power Management

Delay reduction techniques for playout buffering

Incremental View Maintenance for Mobile Databases

Contact Info

Product

Resources

About