The LU file archiver is computer program that combines a number of files together into one archive file or creates a series of archive files for easier storage or transportation. Most basic archivers take a list of files and concatenate their files sequentially into the archive, and store metadata about a file the operating system provides, for example access control. The archive file created with the LU (Library Utility) application creates LBR file extension that stands for library. The archiver normally employs archive formats that support lossless data compression wherein the decompressed file is the same as the original. It creates clusters of files that are frequently pooled into an archive. The created file clusters are typically composed of DOS files with a directory. The .LBR file format was used on CP/M and DOS operating systems during the early 1980s. The process of making an archive is termed archiving or packing, while reconstructing the original files from the archive is called unarchiving, extracting, or unpacking.