Upload/Download Service

We intend to implement at the MPIWG an additional service that will be layered over the repository. This service will offer the following functionality:

• The upload/download layer will provide a name translation service such that at upload time, local files will be associated with their locator in the repository, even though their file name may not be the same as their locator. At download time, files may be assigned a canonical file name that differs from the locator.

• The upload/download layer will ensure via a checksum mechanism that only changed files are uploaded to the repository. At download time, checksums will be computed and stored for downloaded files. When files that have been previously downloaded are submitted for upload, checksums will be regenerated and compared so as to determine whether any changes have been made.

• The upload/download layer will be implemented as a signed Java applet. It will be compatible with Netscape versions 4.5 and higher, Internet Explorer 5.0 and higher, and modern versions of Mozilla.

We anticipate that the upload/download service will be sufficiently general as to be useful to a wide range of projects outside Archimedes, with similar storage and versioning needs.