This articleneeds additional citations forverification. Please helpimprove this article byadding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Digital Data Storage" – news ·newspapers ·books ·scholar ·JSTOR(February 2013) (Learn how and when to remove this message)

This articleprovides insufficient context for those unfamiliar with the subject. Please helpimprove the article byproviding more context for the reader.(August 2021) (Learn how and when to remove this message)

Digital Audio Tape

Media type	Magnetic cassette tape
Encoding	Lossless real-time
Read mechanism	Rotating head
Write mechanism	Rotating head, helical scan
Developed by	Sony
Usage	Data storage
Extended from	Digital Audio Tape
Released	1989; 37 years ago (1989)

Digital Data Storage (DDS) is acomputerdata storage technology based upon theDigital Audio Tape (DAT) format that was developed during the 1980s. DDS is primarily intended for use as off-line storage, especially for generatingbackup copies of working data.

A DDS cartridge uses tape with a width of 3.81mm, with the exception of the latest formats, DAT-160 and DAT-320, both which use 8mm wide tape. Initially, the tape was 60 meters (197 feet) or 90 meters (295 ft.) in length. Advancements in materials technology have allowed the length to be increased significantly in successive versions. A DDS tape drive useshelical scan recording, the same process used by avideo cassette recorder (VCR).

Backward compatibility between newer drives and older cartridges is not assured; the compatibility matrices provided by manufacturers will need to be consulted.^[1] Typically drives can read and write tapes in the prior generation format, with most (but not all) also able to read and write tapes from two generations prior. Notice in HP's article that newer tape standards do not simply consist of longer tapes; with DDS-2, for example, the track was narrower than with DDS-1.

At one time, DDS competed against theLinear Tape-Open (LTO),Advanced Intelligent Tape (AIT),VXA, andTravan formats. However, AIT, Travan and VXA are no longer mainstream, and the capacity of LTO has far exceeded that of the most recent DDS standard, DDS-320.

This sectionis inlist format but may read better asprose. You can help byconverting this section, if appropriate.Editing help is available.(August 2021)

DDS-1

Stores up to 1.3 GB uncompressed (2.6 GBcompressed) on a 60 m cartridge or 2 GB uncompressed (4 GB compressed) on a 90 m cartridge. The DDS-1 cartridge often does not have the -1 designation, as initially it was the only format, though cartridges produced since the introduction of DDS-2 may carry a -1 designation to distinguish the format from newer formats. A media recognition system was introduced with DDS-2 drives and cartridges to detect the medium type and prevent the loading of an improper medium. From 1993, DDS-1 tapes included the media recognition system marks on the leader tape—a feature indicated by the presence of four vertical bars after the DDS logo.

DDS-2

Stores up to 4 GB uncompressed (8 GB compressed) on a 120 m cartridge.

DDS-3

Stores up to 12 GB uncompressed (24 GB compressed) on a 125 m cartridge. DDS-3 usesPRML (Partial Response Maximum Likelihood) to minimize electronic noise for a cleaner data recording.

DDS-4

DDS-4 stores up to 20 GB uncompressed (40 GB compressed) on a 150 m cartridge. This format is also called DAT 40.

DAT 72

DAT 72 stores up to 36 GB uncompressed (72 GB compressed) on a 170 m cartridge. The DAT 72 standard was developed by HP andCertance. It has the same form-factor as DDS-3 and -4 and is sometimes referred to as DDS-5.

DAT 160

DAT 160 was launched in June 2007 by HP, stores up to 80 GB uncompressed (160 GB compressed). A major change from the previous generations is the width of the tape. DAT 160 uses 8 mm wide tape in a slightly thicker cartridge while all prior versions use 3.81 mm wide tape. Despite the difference in tape widths, DAT 160 drives can load DAT-72 and DAT-40 (DDS-4) cartridges. Native capacity is 80 GB and native transfer rate was raised to 6.9 MB/s, mostly due to prolonging head/tape contact to 180° (compared to 90° previously).^[2] Launch interfaces wereParallel SCSI andUSB, withSAS interface released later.

DAT 320

In November 2009 HP announced the DAT-320 standard, which stores up to 160 GB uncompressed (marketed as 320 GB assuming 2:1 compression) per cartridge. Native transfer rate was raised to 12 MB/s.

The next format, Gen 8, was canceled.^{[citation needed]}

• WangDAT
• Data8
• Magnetic storage

Wikimedia Commons has media related toDigital Data Storage.

• DAT Manufacturers Group
• ECMA-139ISO/IEC 10777:1991, Specification ofDDS.ECMA-139
• ECMA-146ISO/IEC 11321:1992, Specification ofDATA/DAT.ECMA-146
• ECMA-150ISO/IEC 11557:1992, Specification ofDDS-DC (DDS w/ compression).ECMA-150
• ECMA-151ISO/IEC 11558:1992, Specification ofDCLZ (compression algorithm).ECMA-151
• ECMA-170ISO/IEC 12447:1993, Specification ofDDS (for 60m and 90m tapes).ECMA-170
• ECMA-171ISO/IEC 12448:1993, Specification ofDATA/DAT-DC (for 60m and 90m tapes).ECMA-171
• ECMA-198ISO/IEC 13923, Specification ofDDS-2.ECMA-198
• ECMA-236ISO/IEC 15521, Specification ofDDS-3.ECMA-236
• ECMA-288ISO/IEC 17462, Specification ofDDS-4.ECMA-288

• Computer storage tape media
• Computer file formats

• CS1 maint: bot: original URL status unknown
• Articles with short description
• Short description is different from Wikidata
• Articles needing additional references from February 2013
• All articles needing additional references
• Wikipedia articles needing context from August 2021
• All Wikipedia articles needing context
• All pages needing cleanup
• Articles needing cleanup from August 2021
• Articles with sections that need to be turned into prose from August 2021
• All articles with unsourced statements
• Articles with unsourced statements from October 2022
• Commons category link is on Wikidata