| Managed by: |
Randal Burns Hopkins Storage Systems Lab Department of Computer Science Johns Hopkins University randal@cs.jhu.edu |
Archive: |
ipdata.tgz |
The archive contains files used in experiments for studying the compression and performance of In-place Reconstruction of Version Differences [1,2]. These algorithms modify a differential encoding of a file so that it may be reconstructed in the space (storage or memory) that the current version occupies. A differential encoding represents data compactly as a set of changes from a previous version of the same data. This differential encoding is transmitted across networks to update older versions. The compact encoding saves both time and bandwidth. In-place reconstruction allows differential encodings to be used on resource constrained devices such as wireless handhelds and cellular phones.
These data should be useful for experiments that wish to study what types of versions arise in mobile and wireless systems. We describe our data [1]:
"The experimental data we collected and employed are characteristic of the intended application. Because our interest lies in distributing files to resource-limited devices, we collected versions of open-source software intended for the Compaq iPAQ handheld device, a personal digital assistant that can run versions of the Linux operating system. Data were obtained in April 2002 from http://www.handhelds.org, a Web site designed to facilitate the `creation of open source software for use on handheld and wearable computers.' To collect data, we downloaded the software archive and ran scripts that search the archive for multiple versions of the same files. All experimental data are files that are distributed to handheld devices: boot loaders, applications, flash updates, and their associated data files. We did not include source code or other data not intended for distribution to handhelds."
The archive contains the following directories:
apps.files
armu.files
blbk.files
fam.files
reflash.files
arm.files
blbin.files
blmono.files
qpe.files
The http://www.handhelds.org Website contained many files organized in high-level groupings apps, armu, fam, etc. We extracted versions of files so that reflash.files contains all versions in the reflash area of the Web site. We define a version as any non-identical files with the same name.
Within each directory, the archive contains version pairs in files "X.name" and "X.name___". In this naming convention, "X" is a number to make each name unique, "name" is the original short name of the file on http://www.handhelds.org and "___" indicates that "X.name.___" is a version of "X.name".
As these files have been extracted from http://www.handhelds.org/ they are subject to the copyright and licensing guidelines imposed at that Website. Please refer to and comply with restrictions as published on their site. The Hopkins Storage Systems Lab place no further copyright or licensing restriction on the data, but we do request that you send an email to randal@cs.jhu.edu that describes how you are using this compilation of versioned files.
[1] R. Burns, L. Stockmeyer, and D. Long. In-Place Reconstruction of Version Differences (see Technical Report HSSL-2002-01). IEEE Transactions on Knowledge and Data Engineering, to appear.
[2] R. Burns, L. Stockmeyer, and D. Long. In-Place Reconstruction of Version Differences. Technical report HSSL-2002-01, Hopkins Storage Systems Lab, Department of Computers Science, Johns Hopkins University, 2002.