Although the LBone makes it easier for the user to find depots and the exNode handles IBP capabilities for the user, the user still has to manually request allocations, store the data, create the exNode, attach mappings to the exNode and insert the IBP allocations and metadata into the mappings. The next layer on the Network Storage Stack is the Logistical Runtime System (LoRS). The LoRS layer consists of a C API and a tool set that automate the finding of IBP depots via the LBone, creating and using IBP capabilities and creating exNodes.

The command line LoRS tools allow users to store files or parts of files into exNodes, add replicas to existing exNodes, remove replicas from existing exNodes, extend an exNode's duration and retrieve all or part of the logical data stored within an exNode. The tools allow users to access many of the features provided by the C API without having to do any programming. The user may specify defaults for many of the tools in a preference file, .xndrc, in the user's home area. A brief command line tutorial is here and the full LoRS Manual is available as a PDF here.

The LoRS library is intended to be included in applications to give them access to exNodes and IBP storage. The LoRS library provides a high level of flexibility for dealing with the lower layers of the Network Storage Stack.

The complete LoRS API documentation is now available online. To view a list of LoRS error numbers, go to http://loci.cs.utk.edu/lors/lors_api/group__lors__api__errors.html.

If you have any questions or suggestions for LoRS, please subscribe to the LoCI interest mailing list or send us an email at


Try the LoRS tools without installing anything. These tools are limited versions of the command line tools. Because the web tools have to use HTTP to send and retrieve the entire file, they work best on files less than 50 MB in size.

Visit the WebLoRS page.

Some Applications that use LoRS

Content Distribution

For Internet2-connected users, we offer the latest Linux and FreeBSD ISO images as well as popular large-format movie trailers. We cache many copies of these files across the US which you can access at high-speed using the provided exNodes and the LoRS tools.

Visit the Linux Distribution page and the Movie Trailer Distribution page.


Forgot to set your VCR before you left home? You are in luck, use IBPvo to record a show from anywhere. After the recording is done, IBPvo will Upload the video and send you the exNode.

Visit the IBPvo page.


Formerly known as IBP-Mail, LoRS-Mail allows you to send large files to other people. Most mail systems will only let a user send a few megabytes (MBs). If somone needs to send hundreds of megabytes or even gigabytes (GBs) of files, it is not easy. Using LoRS-Mail, however, is. The sender can store the file in the network and get an exNode. The sender can then send the exNode to the recipient, and the recipient can then download the data.

Visit the LoRS-Mail page.


The Read-Only Logistical File System is a file system-like storage system for exNodes. ROLFS provides a means for sharing exNodes via namespacing (directories), user/group authentication/authorization, and UNIX-like file permissions.

Java LoRS

Currently, we are working on an initial port of the command line tools and classes that can be used within other Java applications to store data into new exNodes, retrieve data from exNodes, add and remove replicas and refresh exNodes.

Visit the Java LoRS page.