All drives the format used DLT tape poludyuymovoy width, at the time of emergence of this format - it was the most common standard for tape. Using a tape width to increase the amount of recording information. A distinctive feature of DLT-devices is that the reception drum for the tape is not in the tape, and in the drive, which allows more efficient use of volume cartridge. The size of the cartridge in all drives DLT-V/SDLT/DLT-S4 - 10x10 see Sam drive produced several large sizes.

Drives DLT conduct reading and writing linearly on the tape and each track is written along with the data tapes. When reaching the end of the tape, head record perepozitsioniruetsya to another position on the tape and recording begins carried out in the opposite direction. This process will take place until the tape would not be fully recorded.

DLT technology was developed by Quantum, and has now split into two independent project - Value DLT and Super DLT.

Fig.1 Belt nkopitel format DLT

Figure 2 tape drive DLT-drive

Technology Super DLT (SDLT) is the heir DLT, the developer - Quantum and DEC. There is another, better tape, other magnetic heads (CMR, a cluster magnitorezistivnyh heads), optical positioning system tracks and others while retaining compatibility for reading old cartridges for DLTIV SDLT220/320; SDLT600 remains compatible cartridges for reading with SDLT I; DLT-S4 continues to read compatibility with cartridges SDLT II.

Fig.3 tape drive SDLT-drive

The first device SDLT-220 (11/22 MB / s, 110/220 Gb), appeared in early 2001, now comes the second SDLT320 (16/32 MB / s, 160/320 Gb), the third SDLT 600 (36/72 MB / s, 300/600 Gb) and fourth generation of DLT-S4 (60/120 MB / s, 800/1600Gb) respectively

Technology Value DLT (DLT VS) is a side branch DLT, the developer - Benchmark. The standard was created in order to compete with DAT and seize part of the market, the first device DLT VS80 (3 / 6 Mb / s, 40/80 GB), appeared in early 2000. Media - cartridge DLT IV, but the format reading / writing is not compatible with DLT80 and SDLT. Quantum has released streamers second-generation DLT VS160 (8 / 16 Mb / s, 80/160 GB) and third-generation DLT-V4 (160/320 GB)

Fig.4 thin-film structure of magnetic tape

New Perspective Development Plan DLTtape provides for an expansion of two lines of tape drives Quantum. The two new generations are equipped with the function of reading in the opposite direction, will focus on enhancing capacity. The new line of tape, DLT-S ™ (formerly SDLT ™) offers high capacity, combined with high productivity, a new line of DLT-V ™ (formerly DLT VS ™) - a high capacity, combined with reasonable cost of storage. System of the next generation will be able to read data from the old cartridge format. The company will also offer on the basis of their devices, two generations of technology WORM (Write Once, Read Many), prevent the unauthorized removal or overwrite data.

In the next decade of DLT-S reached capacity cartridges for more than 10 Tb and go to the level of performance equipment NAS. A line of DLT-V, over time, will mnogoterabaytnye device costing below $ 1000

Fig.5 DLT Roadmap

In conclusion, that the format DLT, likely will not have to continue, because some technological failures ... yield the palm format LTO / Ultrium in its class. The fact is that the cartridge DLT just above the cartridge LTO, which makes it extremely difficult to install DLT drives in avtoloudery height of 1U. As a result of slightly higher cartridge, the same tape library, but with different drives have different numbers of slots, and this ratio is not in favor of DLT, in the same capacity and speed - is crucial. Virtually all manufacturers avtolouderov libraries and renounced the use of drives DLT-S4 and DLT-V4, except at the very Quantum. There is a third reason: because Quantum is a manufacturer and LTO and DLT, it had to compete himself in a segment of a class of drives.

Despite these problems format Installation base drives DLT / SDLT has, so far, hundreds of thousands of devices through high reliability and durability, as of drives and cartridges. A large number of companies and organizations in its work, continue to use the first-generation drives - DLT4000/7000/8000, widespread and drives SDLT and DLT-S4 and can say with certainty that the device DLT format for a long time will be in demand in the market backup systems.