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The DLT 7000 Tape Drive: A New Level of Performance

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Meeting the Storage Challenges of the 1990s

The DLT 7000 Tape Drive: A New Level of Performance

A Quantum White Paper

Storage Challenges In The Fast-Moving Information Age

The Information Technology revolution is in high gear. Emerging applications including multimedia, imaging, and the Internet are creating exciting opportunities for organizations to develop new products, achieve higher business productivity, explore new business venues, and share information globally.

At the same time, these breakthrough applications are creating enormous data storage challenges that must be resolved if companies are to continue climbing the information technology curve. Indeed, user demand for storing and managing business-critical information is growing dramatically. Storage needs will continue to increase at a compounded annual growth rate of 60 percent, according to the Meta Group. And worldwide sales in the low- and mid-range tape market are projected to reach approximately 8.5 million units by 1999, according to the International Data Corporation (IDC). That's an increase of nearly 85 percent from the 4.6 million units shipped in 1994.

Defining the Challenge

Today's storage challenges require balancing a range of performance, capacity, reliability, and compatibility issues. IS managers are looking for tape storage solutions with faster response, higher data integrity, and reduced overall operating costs. In heavy-duty on-line applications, where data is typically written once and read many times, high performance and durability are critical. To meet these user needs, today's tape products must offer:

  • faster performance

  • higher capacities

  • greater durability and data integrity in heavy-duty-cycle applications

  • flexibility and compatibility in complex computing environments

  • ability to handle leading-edge HSM and real-time data acquisition applications

  • lowest possible cost-per-GB stored

Setting a New Standard

Quantum Corporation has earned a reputation for leadership in the mid-range tape storage market with its DLT tape technology, which is recognized as an industry benchmark for performance with the popular DLT 2000XT and DLT 4000 tape drives.

Now, Quantum continues its tradition of leadership with the introduction of the new DLT 7000 tape drive. The DLT 7000 tape drive offers a significant breakthrough in performance and capacity that sets it apart from other mid-range tape products. This paper illustrates how the DLT 7000 tape drive establishes a new standard in tape drive performance.

The DLT 7000 -- A Breakthrough Solution In Tape Storage

The DLT 7000 tape drive is a half-inch cartridge tape drive that builds upon the worldwide reputation of DLT technology for high reliability in the field while offering a new level of performance and capacity. It's designed for heavy-duty-cycle tape storage environments, including:

  • high-end PC servers

  • UNIX workstations and servers

  • mid-range systems

  • network servers

  • mainframe environments

At the heart of the DLT 7000 tape drive's enhanced capabilities is Quantumís new SPR Recording System, which combines two innovative features ó Symmetric Phase Recording and a Parallel Channel Architecture ó within our industry-leading DLT technology. Together, these enhancements help the DLT 7000 tape drives provide a number of dramatic advantages over other mid-range tape products:

  • Performance Data transfer rate of 5 MB per second (native)

  • Capacity 35 GB per cartridge (native)

  • Data integrity Superior multi-level error detection and correction providing an uncorrected bit error rate specification of 1 x 1017

  • Durability Greater operating life of both hardware and media, with a tape lifetime rated at 1,000,000 passes, a head life of 30,000 hours, and a 200,000 hour MTBF

  • DLT tape family An expanded family of DLT tape drives with backward read/write compatibility

  • Migration path SPR technology provides a solid path for expandability to higher levels of performance and capacity in future products

The DLT 7000 tape drive at a glance

Data rate (MB/sec, native) 5.0

Capacity (GB, native) 35

Bit density (Kbpi) 86

Track density (tpi) 416

Tape speed (in/sec) 160

Media type MP-2

Media length (feet) 1800

Recording channels 4

Data compression DLZ

Interface SCSI-2/Fast/Wide

Typical applications for the DLT 7000 tape drive

Unattended Department/enterprise

back-up/restore server for Fortune 500


Archive Seismic exploration,

digital film archives,

post production

Hierarchical Video-on-demand,

storage document storage,

medical imaging

SPR Technology Delivers Higher Performance and Capacity

The DLT 7000 tape drive's SPR Recording System is Quantum's newest enhancement to its field-proven DLT tape technology. DLT products utilize a linear, serpentine recording approach where data is placed on the tape in longitudinal tracks, allowing the drive to read multiple data channels simultaneously.

The new SPR Recording System offers two features that not only deliver performance and capacity enhancements today but offer a solid migration path for dramatically higher DLT tape drive data transfer rates and cartridge capacities in the future.

Parallel Channel Architecture Offers 5.0 MB Per Second Performance

The DLT 7000 tape drive's Parallel Channel Architecture utilizes a new four-channel read/write system that allows four channels of data to be read or written simultaneously providing an impressive data transfer rate of 5.0 MB per second (native). This rate is greater than 65 percent faster than that of the nearest competitor. With this architecture, individual data blocks are not required to be located on any particular track or in consecutive order. This creates a channel-independent block organization allowing the number of parallel channels to be easily expanded in future DLT tape products for higher data transfer rates.

Symmetric Phase Recording Provides Unprecedented 35 GB Per Cartridge

The DLT 7000 tape drive's innovative new SPR format enhances traditional DLT tape recording by writing adjacent tracks with an alternating head angle. This eliminates cross-track interference and the need for guard bands, making smaller track widths possible. Consequently, the DLT 7000 tape drive achieves a track density of 416 tpi. This higher density allows the DLT 7000 tape drive to provide an unprecedented capacity of 35 GB per cartridge (native), significantly greater than its closest competitor in the mid-range tape marketplace. And with SPR, higher track densities ó and higher cartridge capacities ó are easily obtainable in the future.

The DLT 7000 tape drive's higher cartridge capacity is invaluable in unattended back-up, image/data storage, and archival applications. With more data on fewer cartridges, data can be accessed faster, floor-space costs can be reduced, and operator intervention can be minimized. Ultimately, the cost of an entire tape

storage operation can be lowered by reducing both the capital equipment investment and amount of operator intervention required. This holds true for both standalone tape storage configurations and tape libraries.

Higher cartridge capacity also allows more data to be online for a given number of drives, which is particularly valuable in applications such as imaging, where more image files can be online simultaneously.

Additional Performance Advantages of the DLT 7000 Tape Drive

To achieve maximum overall tape throughput, a tape drive must be able to track the data rate of the host system. If the transfer rate of a tape drive exceeds that of the host, the tape must reposition frequently. DLT™ tape technology employs an ìadaptive cache bufferingî feature to ensure maximum throughput. This feature monitors the host and dynamically adjusts cache buffering operations, minimizing repositioning delays.

Locating files quickly is important for applications that frequently search for files and retrieve or restore data. DLT tape technology minimizes search time through a file mark index located at the logical beginning of the tape. Using this index, the drive ìapproximatesî the location of the selected file and performs a high-speed search to the estimated file location.

Quantum's New SPR Recording System

The SPR format enhances traditional DLT tape recording by writing adjacent tracks with an alternating head angle eliminating cross-track interference and the need for guard bands. This allows for smaller track widths and higher track densities.

Superior Data Integrity

Information is the lifeblood of corporations big and small. The impact of losing essential data, even once, can be disastrous. DLT tape technology addresses this challenge with what is widely recognized as the most comprehensive data integrity capabilities in the mid-range tape marketplace.

The DLT 7000 tape drives use the same advanced error detection and correction techniques proven in previous DLT tape products. This error detection and correction system includes parity, multi-layers of CRC (cyclical redundancy code), error detection code (EDC), and a custom Reed-Solomon Error Correction Code (ECC), to ensure that data is being correctly reproduced throughout the drive's read process, resulting in an undetected bit error rate specification of 1 x 10-27 . The uncorrected error rate specification is less than one uncorrected error in 1 x 1017 bits of data.

Channel Independent Block Organization

The DLT 7000 tape drive's SPR Recording System offers a channel-independent data organization scheme; data and ECC blocks can exist on any of the four channels. Block location is independent, so in the case of a bad block the drive will rewrite on the next available channel. This provides efficient write error handling and allows the unit to write data while a channel is temporarily inoperable.

Some tape technologies can recover data only if the error is measured in tenths of inches. In contrast, the DLT 7000 tape drive can recover all the user data with up to six consecutive inches of tape damages on a single track, or with up to one and one-half inches of tape damaged across all four tracks.

Higher Durability and Longer Head Life

Today's large-scale tape storage applications require higher durability and uptime from both hardware and media. For example, in a typical backup or archiving application a tape drive might be active only 10 percent of the time. In an advanced HSM system, by contrast, the system may be in heavy use nearly 80 percent of the time. Given this type of demand, conventional drives with a head life in the range of 1,000 to 2,000 hours are generally unsuitable for heavy-duty storage applications involving large-scale read/write passes.

Quantum's DLT tape technology is widely recognized around the world for being rugged, reliable, and long-lasting. With DLT tape technology, the drive heads are non-rotating, which means that there is no wear on the heads or the tape media when the tape stops. The DLT 7000 tape drive also employs a patented tension algorithm to minimize tape tension and wear. Each time a tape is loaded, the drive calculates and sets the minimum tension required to achieve high-quality read/write signals. This calibration is used throughout the operational life of the drive to maintain optimal-contact recording.

These advantages allow the DLT 7000 tape drive to offer a head life of 30,000 hours, dramatically longer than any other tape storage product in its class. Its overall MTBF is rated at 200,000 hours, ensuring high system reliability.

Backward Compatibility for Investment Protection

Storage customers today are seeking the highest levels of interoperability and investment protection. Some of the new tape drives recently announced in the marketplace, however, are incapable of reading existing tapes written on older models or of writing new tapes that can be read by their predecessors.

Quantum has gone to significant lengths to ensure that the new 4-channel DLT 7000 tape drive is fully read/write compatible with all previous Quantum DLT tape formats. Thus the DLT 7000 tape drive can both read existing tapes written on the DLT 2000XT and DLT 4000 tape drives, and write tapes that the older models can read.

This full backward compatibility is achieved via the SPR Recording System's innovative new head mechanism. With SPR technology, the head assembly pivots into angled position for 4-channel read/write, and, when required, reverts to a perpendicular position for 2-channel compatibility with tapes written on the DLT 2000XT and DLT 4000 tape drive. Since Quantum's new head mechanism reads and writes both new SPR and traditional DLT recording formats, users can upgrade to the new DLT 7000 tape drive and bring all of their existing tape cartridges with them.

Full Family of Open Systems

Quantum's DLT tape family now offers an expanded selection of compatible drives from the low-end DLT 2000XT tape drive to the high-performance DLT 7000 tape drive. Users can choose from a scaleable family of DLT tape solutions to efficiently address their storage needs. Like previous DLT tape drives, the new DLT 7000 tape drive reflects Quantum's continued commitment to providing standards-based DLT tape products that are robust and open solutions.

The Future of DLT Tape Drives

The demand for higher tape storage performance will continue as users around the world seek to exploit the advantages of HSM, enhancements in CPU speeds, improvements in disk performance, new online applications, and much more. While some tape storage technologies may appear outdated, others are positioned to accommodate this demand for rapid growth in performance, capacity, data integrity, and a low cost-per-GB stored. DLT tape drives are one of those key technologies.

DLT tape technology offers a built-in migration path with room for enhancements in data transfer speed and capacity. Quantum's commitment to the technology is significant, as evidenced by the new SPR Recording System in the DLT 7000 tape drive. Featuring both a new Parallel Channel Architecture and Symmetric Phase Recording, this exciting breakthrough allows Quantum to easily enhance its DLT tape drive line with dramatic future improvements in both system performance and cartridge capacity. This growth path makes DLT tape drives ideally suited to emerging online applications. In addition, high capacity, low cost, and small cartridge size will continue to make DLT tape drives a cost-effective alternative to traditional back-up/archival solutions.

With a compatible and expandable family of DLT tape solutions, it seems clear that Quantum offers a vibrant growth path for meeting the tape storage challenges of tomorrow.

See Also