Linear Tape-Open (or LTO) is a magnetic tape data storage technology originally developed in the late 1990s as an open standards alternative to the proprietary magnetic tape formats that were available at the time. Hewlett-Packard, IBM and Seagate initiated the LTO Consortium, which directs development and manages licensing and certification of media and mechanism manufacturers. Seagate's tape division was spun-off as Certance and is now part of Quantum Corp.
The standard form-factor of LTO technology goes by the name Ultrium, the original version of which was released in 2000 and could hold 100 GB of data in a cartridge. LTO version 6 released in 2012 can hold 2.5 TB in a cartridge of the same size.
Upon introduction, LTO Ultrium rapidly defined the super tape market segment and has consistently been the best-selling super tape format. LTO is widely used with small and large computer systems, especially for backup.
Historical context 
Half-inch (1⁄2-inch, 12.65mm) magnetic tape has been used for data storage for more than 50 years. In the mid 1980s, IBM and DEC put this kind of tape into a single reel, enclosed cartridge. Although the physical tape was nominally the same size, the technologies and intended markets were significantly different and there was no compatibility between them. IBM called its format 3480 (after IBM's one product that used it) and designed it to meet the demanding requirements of its mainframe products. DEC originally called theirs CompacTape, but later it was renamed DLT and sold to Quantum Corp. In the late 1980s, Exabyte's Data8 format, derived from Sony's dual-reel cartridge 8mm video format, saw some popularity, especially with UNIX systems. Sony followed this success with their own 8mm data format, Advanced Intelligent Tape (AIT).
By the late 1990s, Quantum's DLT and Sony's AIT were the leading options for high-capacity tape storage for PC servers and UNIX systems. These technologies were (and still are) tightly controlled by their owners. Consequently, there was little competition between vendors and the prices were relatively high.
IBM, HP and Seagate sought to counter this by introducing a more open format focusing on this market segment. Much of the technology is an extension of the work done by IBM at its Tucson lab during the previous 20 years. Initial plans called for two LTO formats to directly compete with these market leaders. Ultrium was half-inch tape on a single reel, optimized for high-capacity and Accelis was supposed to be 8mm tape on dual-reels, optimized for low-latency.
Around the time of the release of LTO-1, Seagate's magnetic tape division was spun off as Seagate Removable Storage Solutions, later renamed Certance, which was later acquired by Quantum.
LTO Ultrium was developed as a replacement for DLT and has a similar design of 1⁄2-inch wide tape in a (slightly smaller) single reel cartridge. This made it easy for robotic tape library vendors to convert their DLT libraries into LTO libraries.
- An Ultrium cartridge's dimensions are 102.0 × 105.4 × 21.5 mm.
- An Ultrium drive reads data from a cartridge in its own generation and at least the two prior generations.
- An Ultrium drive writes data to a cartridge in its own generation and to a cartridge from the immediate prior generation in the prior generation format.
As of December 2012[update] LTO-6 was the latest generation; further generations are planned as tabulated below.
|Release date||2000||2003||2005||2007||2010||Dec. 2012||TBA||TBA|
|Native data capacity||100 GB||200 GB||400 GB||800 GB||1.5 TB||2.5 TB||6.4 TB||12.8 TB|
|Max uncompressed speed (MB/s)||20||40||80||120||140||160||315||472|
|Compression capable?||ALDC "2:1"||LTO-DC "2.5:1"||Planned "2.5:1"|
|Partition capable?||No (1 allowed)||Yes (2 allowed)||Yes (4 allowed)||Planned|
|Tape thickness||8.9 µm||8 µm||6.6 µm||6.4 µm||6.1 µm|
|Tape length||609 m||680 m||820 m||846 m|
|Wraps per band||12||16||11||14||20||34|
|Linear density (bits/mm)||4880||7398||9638||13,250||15,142||15,143|
|Encoding||RLL 1,7||RLL 0,13/11; PRML||RLL 32/33; PRML||32/33 RLL NPML|
|Cartridge memory||4 KiB||8 KiB||16 KiB:5|
- Specifications announced January 19, 2010. The first LTO-5 drives appeared on the market in Q2, 2010.
- Nearly doubled capacity to 1.5 TB (1500 GB)
- Increased data transfer rate to 140 MB/s (maximum).
- Introduced partition feature that allows tape to be "split" into two separately writable areas. This feature is required by LTFS.
- Licensing Specifications announced June 11, 2012.
- Increased capacity to 2.5 TB
- Increased estimated data-compression ratio due to a larger compression buffer.
- Increased cartridge memory to 16 KiB
- Increased data transfer rate to 160 MB/s (max).
- Data capacity and speed figures above are for uncompressed data. Most manufacturers list compressed capacities on their marketing material. Capacities are often stated on tapes as double the actual value; they assume that data will be compressed with a 2:1 ratio (IBM uses a 3:1 compression ratio in the documentation for its mainframe tape drives. Sony uses a 2.6:1 ratio for SAIT). See LTO-DC below.
- The units for data capacity and data transfer rates generally follow the "decimal" SI prefix convention (e.g. mega = 106) and not the binary prefix convention (e.g. mega = 220).
- Minimum and maximum reading and writing speeds are drive-dependent.
Positioning times 
While specifications vary somewhat between different drives, a typical LTO-3 drive will have a maximum rewind time of about 80 seconds and an average access time (from beginning of tape) of about 50 seconds.[dead link] Note that because of the serpentine writing, rewinding often takes less time than the maximum. If a tape is written to full capacity, there is no rewind time, since the last pass is a reverse pass leaving the head at the beginning of the tape.
Tape durability 
- 15 to 30 years archival.
- 5000 cartridge loads/unloads
- Approximately 260 full file passes. (One full pass is equal to writing enough data to fill an entire tape.)
|General specifications||Lifetime tape durability||Approximate years of life
assuming one tape filled...
|Tape type||Native capacity||Total tracks||Tracks written
|Passes to write
|... per month||... per week|
There is a large amount of lifespan variability in actual use:
- Regularly writing only 50% capacity of the tape results in half as many end-to-end tape passes for each scheduled backup, and doubles the tape lifespan.
- LTO uses an automatic verify-after-write technology to immediately check the data as it is being written, but some backup systems explicitly perform a completely separate tape reading operation to verify the tape was written correctly. This separate verify operation doubles the number of end-to-end passes for each scheduled backup, and reduces the tape life by half.
Technical features 
Linear Tape File System 
- Files and directories to appear on desktop and directory listings
- Drag-and-drop files to/from tape
- File level access to data
- Supports data exchange
With LTFS the drive may behave like a disk (drive) but it is still a tape with serial access. If a file is removed from the listing the associated tape blocks used are not freed up, they are simply marked as unavailable. Files are always appended to the end of the tape.
Unlike a disk LTFS does not know the concept of permission and ownership. In the Unix/Linux world all files and directories on the tape are owned by root. One cannot chown or chmod items on tape. This makes LTFS unattractive as a backup solution - one still needs a third party application to manage the metadata (ownership, permission and timestamps).
Tape layout 
LTO Ultrium tape is laid out with four wide data bands sandwiched between five narrow servo bands. The tape head assembly straddles two adjacent servo bands, with 2 servo read heads and 8 or 16 data read/write heads. Each data head moves up and down within its own data sub-band the same width as the servo band. First, the head assembly is positioned so all tape heads are at the top of their sub-bands and 8 or 16 tracks are written in the forward direction. Then the head assembly is moved to the bottom of each sub-band and 8 or 16 tracks are written in the reverse direction. The set of tracks written at the same time is referred to as a "wrap". Alternating forward and reverse wraps are written as each data sub-band is filled up in 0, 2, 4, ..., 5, 3, 1 order.
When the first data band is filled (they are actually filled in 3, 1, 0, 2 order across the tape), the head assembly is moved to the second data band and a new set of wraps is written. The total number of tracks on the tape is (4 data bands) × (11–20 wraps per band) × (8 or 16 tracks per wrap). For example, an LTO-2 tape has 16 wraps per band, and thus requires 64 passes to fill.
The block structure of the tape is logical so interblock gaps, file marks, tape marks and so forth take only a few bytes each. In LTO-1 and LTO-2, this logical structure has CRC codes and compression added to create blocks of 403,884 bytes. Another chunk of 468 bytes of information (including statistics and information about the drive that wrote the data and when it was written) is then added to create a 'dataset'. Finally error correction bytes are added to bring the total size of the dataset to 491,520 bytes (480 KiB) before it is written in a specific format across the eight heads. LTO-3 and LTO-4 use a similar format with 1,616,940-byte blocks.
New for LTO-3 was write once read many (WORM) capability. This is normally only useful for legal record keeping. An LTO-3 or later drive will not erase or overwrite data on a WORM cartridge, but will read it. A WORM cartridge is identical to a normal tape cartridge of the same generation with the following exceptions: the cartridge memory identifies it to the drive as WORM, the servo tracks are slightly different to allow verification that data has not been modified, the bottom half of the cartridge shell is gray, and it may come with tamper-proof screws. WORM-capable drives immediately recognize WORM cartridges and include a unique WORM ID with every dataset written to the tape. There is nothing different about the tape medium in a WORM cartridge.
Compliance-Verified licensed manufacturers of LTO technology media are 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. Verbatim and Quantegy both licensed LTO technology, but never manufactured their own compliance-verified media.
The colors of LTO Ultrium cartridge shells are mostly consistent, though not formally standardised. HP is the notable exception. Sometimes similar, rather than identical, colors are used by different manufacturers (slate-blue and blue-grey; green, teal, and blue-green).
|Compliance-verified media manufacturers|
|HP||Orange||Blue||Dark red||Yellow||Green||Lt blue||Purple|
|Tandberg Storage||Grey||Black||Purple||Blue-grey||Teal||Dk red||Black|
- UCC means universal cleaning cartridge, which works with all drives.
- Different manufacturers use different names for the same color sometimes. The names in the table above come from each manufacturer's own documentation.
- WORM (write once, read many) cartridges are two-tone, the top half of the shell is the normal color of that generation for that manufacturer, and the bottom half of the shell is a light grey.
Cartridge memory 
Every LTO cartridge has a cartridge memory chip inside it. It is made up of 256 (128 on LTO-1, 2 and 3) blocks of memory, where each block is 32 bytes for a total of 8 KB (4 KB on LTO-1, 2 and 3). This memory can be read or written, one block at a time, via a non-contacting passive RF interface. This memory is used to identify tapes, to help drives discriminate between different generations of the technology, and to store tape-use information.
Every LTO drive has a cartridge memory reader in it. The non-contact interface has a range of 20 mm. External readers are available, both built into tape libraries and PC based. One such reader, Veritape, connects by USB to a PC and integrates with analytical software to evaluate the quality of tapes. This device is also rebranded as the Spectra MLM Reader and the Maxell LTO Cartridge Memory Analyzer.
Leader pin 
The tape inside an LTO cartridge is wound around a single reel. The end of the tape is attached to a perpendicular leader pin that is used by an LTO drive to reliably grasp the end of the tape and mount it in a take-up reel inside the drive. When a cartridge is not in a drive, the pin is held in place at the opening of the cartridge with a small spring.
A common reason for a cartridge failing to load into a drive is the misplacement of the leader pin as a result of the cartridge having been dropped. The plastic slot where the pin is normally held is deformed by the drop and the leader pin is no longer in the position that the drive expects it to be.
Older single-reel tape technologies used different means to load tape onto a take-up reel.
The LTO cartridge label uses the bar code symbology of USS-39. A description and definition is available from the Automatic Identification Manufacturers (AIM) specification Uniform Symbol Specification (USS-39) and the ANSI MH10.8M-1993 ANSI Barcode specification.
The magnetic servo tracks on the tape are factory encoded. Using a bulk eraser (or otherwise exposing the cartridge to a strong magnetic field) will erase the servo tracks along with the data tracks, rendering the cartridge unusable.
Although keeping a tape drive clean is important, normal cleaning cartridges are abrasive and frequent use will shorten the drive's lifespan. LTO drives have an internal tape head cleaning brush that is activated when a cartridge is inserted.
The LTO specification describes a Data Compression method LTO-DC, also called Streaming Lossless Data Compression (SLDC). It is very similar to the algorithm ALDC which is a variation of LZS (a patent-encumbered algorithm controlled by Hi/Fn).
The primary difference between ALDC and SLDC is that SLDC does not apply the compression algorithm to uncompressible data (i.e. data that is already compressed or sufficiently random to defeat the compression algorithm). Every block of data written to tape has a header bit indicating whether the block is compressed or raw. For each block of data that the algorithm works on, it saves a copy of the raw data. After applying the compression function to the data, the algorithm compares the "compressed" data block to the raw data block in memory and writes the smaller of the two to tape. Because of the pigeonhole principle, every lossless data compression algorithm will end up increasing the size of some inputs. The extra bit used by SLDC to differentiate between raw and compressed blocks effectively places an upper bound on this data expansion.
LTO-DC achieves an approximately 2:1 compression ratio when applied to the Calgary Corpus. This is inferior to slower algorithms such as gzip, but similar to lzop and the high speed algorithms built into other tape drives. It should be noted that plain text, raw images, and database files (TXT, ASCII, BMP, DBF, etc.) typically compress much better than other types of data stored on computer systems. In contrast, encrypted data and pre-compressed data (PGP, ZIP, JPEG, MPEG, MP3, etc.) would normally increase in size, if data compression was applied. In some cases this data expansion could be as much as 15%. With the SLDC algorithm, this significant expansion is avoided.
The LTO-4 specification added a feature to allow LTO-4 drives to encrypt data before it is written to tape. All LTO-4 drives must be aware of encrypted tapes, but are not required to actually support the encryption process. The algorithm used by LTO-4 is AES-GCM, which is an authenticated, symmetric block cipher. The same key is used to encrypt and decrypt data, and the algorithm can detect tampering with the data. Tape drives, tape libraries, and backup software can request and exchange encryption keys using either proprietary protocols, or an open standard like OASIS' Key Management Interoperability Protocol.
Error detection and correction 
The tape drives use a strong error correction algorithm that makes data recovery possible when lost data is within one track. Also, when data is written to the tape it is verified by reading it back using the read heads that are positioned just 'behind' the write heads. This allows the drive to write a second copy of any data that fails the verify without the help of the host system.
The price of tape drives and tape media has increased relative to hard disk drives, as disk prices dropped. As of 2013[update] the cost of an LTO-5 drive taking tapes of up to 1.5 TB true (uncompressed) capacity was about US$1800. As of 2013[update] the media is cheaper than a disk drive, as a 1.5 TB magnetic tape cartridge costs about US$40 where as a disk drive with the same capacity costs about US$70 to US$100.
Sales figures 
The presence of five certified media manufacturers and four certified mechanism manufacturers has produced a competitive market. This has led to attractive prices for customers and high sales volumes for manufacturers. In 2002 LTO out-shipped SDLT by nearly 2 to 1. Sales since then have dominated other "super" formats (SDLT, SAIT). As a result, Quantum discontinued development of new DLT products in February 2007 and Sony followed suit by declaring AIT End-of-Life in March 2010.
|Total drives sold
(as of Sept.)
sold this year
|Total cartridges sold
(as of Sept.)
Unsuccessful LTO variants 
Some planned LTO variations were not produced, or produced only briefly.
LTO technology was originally designed to come in two form factors, Ultrium and Accelis. As of 2008 LTO Ultrium was very popular and there were no commercially available LTO Accelis drives or media. In common usage, LTO generally refers only to the Ultrium form factor.
Accelis was developed in 1997 for fast access to data by using a two-reel cartridge that loads at the midpoint of the 8 mm wide tape to minimize access time. IBM's (short-lived) 3570 Magstar MP product pioneered this concept. The real-world performance never exceeded that of the Ultrium tape format, so there was never a demand for Accelis and no drives or media were commercially produced.
Multiple lengths of LTO-1 tapes 
The first generation of Ultrium tapes were going to be available with four types of cartridge, holding 10 GB, 30 GB, 50 GB, and 100 GB. Only the full length 100 GB tapes were produced.
HP LTO-1 cleaning strategy 
HP LTO Gen.1 drives have a cleaning strategy that will prevent the drive from actually using the cleaning tape if it is not needed. In a change of strategy, HP LTO Gen 2, 3 and 4 drives will always clean when a Universal Cleaning Cartridge is inserted, whether the drive requires cleaning or not.
- "SUPER TAPE DRIVE SHIPMENTS DOUBLE IN 2002" (PDF). Archived from the original on 2005-03-06. Retrieved 2013-03-29.
- "New Freeman Study Projects Major Shifts In Compact Tape--- Industry Growth In Units, Revenue Seen" (PDF). Archived from the original on 2005-03-06. Retrieved 2013-03-29.
- "HP, IBM, And SEAGATE Agree To Establish Open Format Specifications For Enterprise And Network Storage" (Press release). LTO. November 4, 1997. Retrieved 2007-10-15.
- "IBM storage history". 03.ibm.com. Retrieved 2013-03-29.
- "LTO cartridge specifications from Fujifilm". Fujifilmusa.com. Retrieved 2013-03-29.
- from Quantum and Tandberg, Bechtle Direct catalog 09/2012, p. 450
- "The Linear Tape File System". 2010.
- "Licensing Specs for LTO-6 Available in August, 2012". Micro-Journal / The LTO Program.
- "Ultrium Generations LTO". Hewlett-Packard, IBM and Quantum.
- "Chris Mellor". The Register. 2010-04-15.
- "Fujifilm LTO-6 specifications" (PDF). Retrieved 2013-03-29.
- Rivera, Rogelio; Vargas, Gustavo; Vázquez, Marco (September 2012), IBM® System Storage® LTO Ultrium 6 Tape Drive Tape Drive Performance White Paper, IBM Guadalajara, "This new capacity is achieved in the same tape length (846m) as the gen5 media due to a higher density format (gen6 format)." Note that another IBM announcement disagrees: "This is achieved by increasing the linear density, track density, and the media length." (IBM TS1060 LTO-6 tape drive announcement, p. 3.) Note: the difference on the length from LTO5 and LTO6 media is only 1 m.
- IBM System Storage TS1060 Tape Drive offers an Ultrium 6 Tape Drive for the TS3500 Tape Library, IBM, 2012-10-03, IBM Hardware Announcement, retrieved 2012-11-05, "There are 2,176 data tracks in Ultrium 6 versus 1,280 data tracks in Ultrium 5."
- "LTO-5 Tape Drive User's Guide". Quantum.
- "LTO-6/LTO-5 Tape Drive Datasheet". Quantum.
- "Linear Tape-Open Program Ships One Million Ultrium Tapes in First 12 Months of Availability for market" (PDF) (Press release). LTO. November 5, 2001.
- "Standard ECMA-319, Ultrium-1". Ecma-international.org. Retrieved 2013-03-29.
- "HP, IBM Pass LTO Ultrium Format Generation 2 Mechanism Compliance" (PDF) (Press release). LTO. February 12, 2003.
- "LTO Program Announces LTO Ultrium Generation 2 Compliance-Verified Licenses" (PDF) (Press release). LTO. March 27, 2003.
- "Fujifilm, Imation, Maxell, Sony, TDK Pass LTO Ultrium Generation 3 Data Interchange Compliance Testing" (PDF) (Press release). LTO. November 8, 2004.
- "HP And IBM Pass Mechanism Compliance Testing For LTO Ultrium Format Generation 4 Tape Drives" (Press release). LTO. April 11, 2007. Retrieved 2007-10-15.
- "Fujifilm, Imation, Maxell, Sony and TDK Pass LTO Ultrium Generation 4 Data Interchange Compliance Testing" (PDF) (Press release). LTO. May 7, 2007.
- "LTO-5 expected in H1 2010 with 1.6 TB – 3.2 TB storage". Geekzone.co.nz:80. Retrieved 2013-03-29.
- "Trust LTO website". Trustlto.com. Retrieved 2013-03-29.
- "LTO Program Frequently Asked Questions". Lto.org. 2010-04-04. Retrieved 2013-03-29.
- Dell PowerVaultTM 110T drive specification. Retrieved 2009-05-16.
- HP Ultrium Media QuickSpecs, version 13 DA-11529, March 29, 2010
- "Oracle and Sun". Sun.com. 2011-10-04. Retrieved 2013-03-29.
- [dead link]
- "Ultrium - LTO Technology - LTO Technology - Primer 3". Lto.org. 2010-04-04. Retrieved 2013-03-29.
- "IBM LTO Gen5 drive". 03.ibm.com. Retrieved 2013-03-29.
- "Patent application number 20090208018: Data Transfer Device". Faqs.org. Retrieved 2013-03-29.
- "Image of Dell LTO-3 WORM cartridge with gray bottom". Support.dell.com. 2012-06-06. Retrieved 2013-03-29.
- "HP Forum: LTO 3 WORM info". H30499.www3.hp.com. Retrieved 2013-03-29.
- "LTO Compliance-Verified Licencees". Ultrium.com. Retrieved 2013-03-29.
- "EMTEC, IMATION, and VERBATIM License Linear Tape-Open Technology" (PDF) (Press release). LTO. August 3, 1998.
- "Linear Tape-Open (LTO) Technology Continues Licensee Momentum with Signing of Fujitsu and Quantegy" (PDF) (Press release). LTO. October 21, 1998.
- Dark Red Fujifilm LTO-5 cartridge[dead link]
- "Black Imation LTO-6 WORM cartridge". Retrieved 2013-03-29.
- "Green HP LTO4 cartridge". Retrieved 2013-03-29.
- Lt Blue HP LTO5 WORM cartridge
- "Slate Blue IBM LTO-4 cartridge". Retrieved 2013-03-29.
- "TS2350 (3580)" (PDF). Retrieved 2013-03-29.
- Dark Red Imation LTO-5 cartridge
- "Black Imation LTO-6 cartridge". Retrieved 2013-03-29.
- Purple Maxell LTO-2 cartridge[dead link]
- Blue-Gray Maxell LTO-3 WORM cartridge[dead link]
- "Dark Red Maxell LTO-5 cartridge". Retrieved 2013-03-29.
- "Black Maxell LTO-6 Cartridge". Retrieved 2013-03-29.
- "Dark Red Sony LTO-5 cartridge". B2b.sony.com. Retrieved 2013-03-29.
- "Dark Red TDK LTO-5 cartridge". Retrieved 2013-03-29.
- "Fujitsu Cartridge Memory documentation" (PDF). Retrieved 2013-03-29.
- "VeriTape the trusted Cartridge Quality Analyzer". Mptapes.com. 2010-06-15. Retrieved 2013-03-29.
- "Spectra MLM Reader". Spectralogic.com. 2007-11-15. Retrieved 2013-03-29.
- "Maxell LTO Cartridge Memory Analyzer". Maxell-usa.com. Retrieved 2013-03-29.
- ECMA 321 – Specification of SLDC
- IBM ALDC documentation
- "Patent claim by Hi/Fn". Retrieved 2013-03-29.
- "HP LTO-4 encryption whitepaper, p11". H20195.www2.hp.com. Retrieved 2013-03-29.
- Maxell tape specs
- "Freeman Reports". Freeman Reports. Retrieved 2013-03-29.
- LTO consortium press releases[dead link]
- "LTO Ultrium Format Maintains Momentum with More Than 1,500,000 Tape Drives and 50,000,000 Cartridges Shipped" (Press release). LTO. September 25, 2006. Retrieved 2007-10-15.
- "More Than 2,000,000 LTO Ultrium Format Tape Drives and 80,000,000 Cartridges Shipped" (PDF) (Press release). LTO. September 5, 2007. Retrieved 2008-03-13.
- "LTO Ultrium Format Reaches New Heights with Over 100 Million Cartridges Shipped" (PDF) (Press release). LTO. September 3, 2008. Retrieved 2009-03-10.
- "LTO ULTRIUM TAPE DRIVE SHIPMENTS CRUISE PAST NEW MILESTONE" (PDF) (Press release). LTO. March 18, 2010. Retrieved 2011-05-17.
- "Advanced Research, Exabyte, Matsushita, Mitsumi Electric and Otari License Linear Tape-Open Technology". Findarticles.com. Retrieved 2013-03-29.
- "What Happened to Accellis?". Enterprisestorageforum.com. 2002-09-11. Retrieved 2013-03-29.
- "EMTEC site offering LTO-1 tape cartridges in multiple sizes". Web.archive.org. 2005-05-09. Retrieved 2013-03-29.
- "HP cleaning strategy". Sundds-lto.com. Retrieved 2013-03-29.
- IBM's LTO Redbook – IBM System Storage Tape Library Guide for Open Systems
- Linear Tape Open – Consortium Homepage
- ECMA 319 – Specification of Ultrium 1
- IBM LTO Ultrium Cartridge Label Specification, Revision 3
- An online generator for LTO barcode labels
See also 
|Wikimedia Commons has media related to: Linear Tape-Open|