which uses a standard XML schema, is readable by any LTFS-aware system and can be modified separately from the data it describes. The Linear Tape File System Technical Work Group of the Storage Networking Industry Association (SNIA) works on the development of the format for LTFS. Without LTFS, data is generally written to tape as a sequence of nameless "files", or data blocks, separated by "filemarks". Each file is typically an archive of data organized using some variation of tar format or proprietary container formats developed for and used by backup programs. In contrast, LTFS utilizes an XML-based index file to present the copied files as if organized into directories. This means LTFS-formatted tape media can be used similarly to other removable media (USB flash drive, external hard disk drive, and so on). While LTFS can make a tape appear to behave like a disk, it does not change the fundamentally sequential nature of tape. Files are always appended to the end of the tape. If a file is modified and overwritten or removed from the volume, the associated tape blocks used are not freed up: they are simply marked as unavailable, and the used volume capacity is not recovered. Data is deleted and capacity recovered only if the whole tape is reformatted. In spite of these disadvantages, there are several use cases where LTFS-formatted tape is superior to disk and other data storage technologies. While LTO seek times can range from 10 to 100 seconds, the streaming data transfer rate can match or exceed disk data transfer rates. Additionally, LTO cartridges are easily transportable and the latest generation can hold more data than other removable data storage formats. The ability to copy a large file or a large selection of files (up to 1.5 TB for LTO-5 or 2.5 TB for LTO-6) to an LTFS-formatted tape, allows easy exchange of data to a collaborator or saving of an archival copy. Cartridges , only Fujifilm and Sony continue to manufacture current LTO media. Compliance-verified licensed manufacturers of LTO technology media at one time were EMTEC, Imation, Fujifilm, Maxell, TDK, and Sony. All other brands of media are manufactured by these companies under contract. Since its bankruptcy in 2003, EMTEC no longer manufactures LTO media products. Imation ended all magnetic tape production in 2011, but continued making cartridges using TDK tape. They later withdrew from all data storage markets, and changed