Quantum DLTtape Handbook ® ™ Your Complete Guide to Today’s Hottest Storage Technology Eighth Edition FROM QUANTUM CORPORATION i
Notice Editor Peter McGowan g•m marketing communications Associate Editor Stephen Weekley Quantum Corporation Senior Writer Hank Giles g•m marketing communications Art Director Christine Koch Knockout Graphics Illustrator Steve Hussey Copyright ©1997, 1998, 2000, 2001 Quantum Corporation QUANTUM CORPORATION 501 Sycamore Drive Milpitas, CA 95035 1-800-624-5545 www.quantum.com or www.DLTtape.com Quantum and the Quantum logo are trademarks of Quantum Corporation, registered in the U.S.A. and other countries.
Foreword The world of data storage has changed a great deal since we published the first Quantum DLTtape™ Handbook in 1997. In just this short time, the role of storage has evolved dramatically. It has become clear that effective storage strategies are fundamental to the success of virtually any information technology strategy, whether it’s in re-energized smokestack industries or e-commerce.
DLTtape system as the dominant tape technology for backup, recovery, archiving, vaulting, near on-line storage, and multimedia storage hierarchies. Because Super DLTtape technology is the newest development in DLTtape systems, we have included in this edition of the handbook a great deal of new information specific to Super DLTtape technology.
Contents Chapter Page — — — — — — — — — — — — — — — — — — — vii Introduction 1. The Evolving Tape Storage Market 2. What is the DLTtape System? 3. History of DLTtape Technology 4. Why Customers Want the DLTtape System 5. Reliability: The Heart of the DLTtape System 6. Demystifying Tape Drive Specs 7. DLTtape Media 8. Automation 9. Horizontal Applications 10. Vertical Market Applications 11. DLTtape System Technology Compared 12. Evaluating the Cost of a DLTtape Backup Solution 13.
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Introduction This handbook will introduce you to one of the dominant forces in mid-range storage technology – the DLTtape systems, including the new Super DLTtape systems. These systems are the acknowledged market-share leaders in mid-range tape backup and archiving, thanks to their remarkable performance, reliability, and storage capacity. Convergence Emergence Why has a seemingly mundane topic like backup and archiving become such a hot subject in recent years? There are several answers.
• A shrinking “window” for backup and archiving. • The emergence of enterprise level storage management strategies, including Storage Area Networks. In this handbook, we will show you why DLTtape and Super DLTtape drives and media are the best storage solutions for these and many of the other storage challenges you may face. We will also help you evaluate your DLTtape storage options and pick the solution that’s right for you.
The Evolving Tape Storage Market 1 Before we plunge into the story of the DLTtape system, we need some context. Who’s buying DLTtape drives and media? And, more importantly, WHY? In this chapter, we’ll walk you through some of the market forces that are impacting the industry, including: • Trends in computing systems: moving away from centralized computing, toward a client/server model. • Moving to centralized management of distributed systems. • Growth of mission critical, leading edge applications.
Worldwide Server Capacity (in Petabytes) 4,500 4,000 3,500 3,000 Centralized Network 2,500 2,000 1,500 Centralized Administration 1,000 Distributed Workgroups 500 0 SOHO Networks 1999 2000 2001 2002 2003 2004 Source: Strategic Research Corp., Network Demographics, 2000 Figure 1-1 Worldwide Server Capacity is one measure of data to be backed up. The figure is climbing at a much steeper rate than the rate of tape shipments.
Worldwide SAN and NAS Revenues in $ Billions 20 16 12 NAS 8 SAN 4 0 1999 2000 Source: IDC December 2000 2001 2002 2003 2004 Figure 1-2 SAN and NAS Disk Shipment Revenues will continue to grow quickly as these storage concepts are implemented widely. computing.
Worldwide Fibre Channel Hub and Switch Revenue ($M) 3,000 2,500 2,000 1,500 1,000 500 0 1997 1998 Source: IDC April 2000 1999 2000 2001 2002 2003 Figure 1-3 Worldwide Fibre Channel Hub and Switch Revenues. Storage Area Networks (SANs) incorporating Fibre Channel technology will grow as the preferred enterprise storage strategy, as evidenced by the projected growth in Fibre Channel network hardware revenues.
Time Regime System Management Location of Data Management Location of Data Early 1980s Glass House Central Central Late 80s–90s Client/Server Distributed Distributed Late 90s Professionally Managed Central Distributed Early 2000s Automated Central and Distributed Central and Distributed Figure 1-4 The Storage Management Evolution shows a transition to recentralized storage management and a continuation of distributed data resources.
gies. There is a greater demand for standard solutions, and robust, highly reliable systems for mission critical applications. Large, global enterprises demand global backup and disaster recovery plans. The system-level trends we’ve been talking about – the move to client/server, the emergence of Storage Area Networks, and the strong trend toward centralized management of distributed storage resources – are increasing the demand for bigger, smarter tape backup systems.
Vertical Markets Growth in specific vertical markets is pushing the demand for better backup solutions. Internet/Intranet applications are growing at a very fast rate. They are driving the sales of servers, and they are also driving the sale of a large amount of storage capacity. An increase in storage capacity always drives the need for more backup capacity. Internet and Intranet applications, impose heavy backup demands for several reasons.
Content is Everything Another trend driving the DLTtape system market is the shift in application content. When images, color, full motion video, and audio are added to the content mix, storage requirements explode. This growth is generating demand for high capacity storage, and for backup. Applications that use non-traditional content have other requirements beyond just size. For instance, these applications often involve distribution of content (for example, programming for video-on-demand applications).
SDLT 220 drive DLT 8000 drive DLT 4000 drive DLTtape III DLT1 drive DLTtape IIIXT DLTtape IV Super DLTtape I Figure 1-5 DLTtape System Product Family includes the DLT 4000 drive, the DLT 8000 drive, the DLT1 drive and the SDLT 220 drive, as well as the DLTtape III, DLTtape IIIXT, DLTtape IV, and Super DLTtape I cartridges. DLTtape drives are available in desktop and system-installable units. new technologies come out.
DLT 4000 DLT 7000 DLT1 DLT 8000 SDLT 220 Capacity (GB, native) 20 35 40 40 110 Data Rate (MB/s, native) 1.5 5.0 3.0 6.0 11.0 Bit Density (Kbpi) 82.5 86.0 123.0 98.0 131.
the Super DLTtape systems, leapfrog current and proposed competitive technologies, with first generation Super DLTtape products offering transfer rates of 11MB/s and capacity of 110GB, advancing to at least one terabyte (uncompressed) over multiple generations (see Chapter 17 for a product roadmap). The biggest barrier to adoption of new tape formats is that users are very reluctant to change backup technologies unless the benefits are overwhelming and compelling.
Worldwide Revenue Market Share, 2000 Sony 11% Exabyte 11% Quantum 78% Source: Dataquest, Preliminary March 2001 Figure 1-7 The DLTtape System Is the Overwhelming Choice among high-performance tape systems. happier “out of the box” experience for users. There is also a trend toward providing more user-friendly graphical displays that show the user exactly what’s going on with backup, where the process stands at the moment, and what and where a hangup is occurring.
of needs. For example, we may see the emergence of a distinct class of “desktop” DLTtape libraries aimed at video and graphic arts applications, while a class of mid-range to very large libraries may be targeted for Storage Area Network (SAN) applications. The Last Word In any discussion of the market for DLTtape technology, the bottom line has to be market share (see Figure 1-7).
What Is the DLTtape System? 2 In later chapters we will cover a great deal of technical information about exactly how DLTtape system technology works. In this chapter we focus on what it is about the DLTtape and Super DLTtape systems that makes them unique. When you examine the details, there are dozens of differences between the DLTtape system and other tape systems. In this chapter we stick to the major points. Some are obvious, and some are invisible, buried inside the product.
Head Head guide assembly Cartridge Take-up reel Figure 2-1 Super DLTtape Drive delivers industry-leading capacity, reliability, and data transfer rate in a 5.25" form factor. Half-Inch Tape The DLTtape system uses half-inch wide tape. That is the widest tape available. The half-inch format was originally used in mainframe products and was adopted by Digital Equipment Corporation when they designed the ancestors of the DLTtape system.
DLTtape drive recording Helical scan recording Figure 2-2 The DLTtape System’s Linear Serpentine Recording pattern writes data along tracks from one end of the DLTtape cartridge to the other. Helical scan systems use read/write heads on a rotating drum to record data in angled stripes across the tape. of the tape is reached, the heads are repositioned to record a new set of tracks, and the tape is again recorded on its whole length, this time in the opposite direction.
Track 2 3mils Track 1 Track 0 Bottom edge of tape Tape Direction Figure 2-3 DLT 4000 Drive writes data on two channels simultaneously in linear tracks that run the length of the tape. The system has a capacity of 20GB native and 40GB compressed. Track 4 Track 3 Track 2 1.
Read Heads Write Heads Write Heads Head Motion Figure 2-5 DLT 4000 Read/Write Head writes data with the tape running either forward or backward, and performs a read-after-write in either direction to ensure accuracy. Read Heads Write Heads Write Heads Head Motion Figure 2-6 DLT 7000 and DLT 8000 Read/Write Head features 4 channels for a data transfer rate of up to 6MB/s (native). Center row of read elements provides read-after-write data accuracy.
adjacent tracks. This data recording technique is called Symmetric Phase Recording™ (SPR). SPR’s herringbone pattern eliminates the need for guard bands and thus allows greater track density. Figures 2-5 and 2-6 show the arrangement of read/write elements on the two-channel DLT 4000 heads and the four-channel DLT 7000 and DLT 8000 heads. When reading DLTtape cartridges recorded on earlier models, the DLT 7000 and DLT 8000 read/write heads automatically shift to a vertical orientation.
Head Drive Leader Take-up Reel Tach Assembly Figure 2-8 The Patented DLTtape Head Guide Assembly, first incorporated in the TF85 drive, is one of the keys to DLTtape reliability. Six precision rollers provide a gentle tape path for long tape life. Head Drive Leader Head Guide Rollers Take-up Reel Figure 2-9 The Super DLTtape Head Guide Assembly is a refined version of the DLTtape Head Guide Assembly. It incorporates only four rollers, further reducing contact and tape wear.
Figure 2-10 DLTtape System Tape Path Is Key reason for the industry-leading reliability, long life, and accuracy of DLTtape technology. Six precision rollers guide tape to internal take-up reel. Figure 2-11 Super DLTtape System Tape Path is even simpler than that of the DLTtape drive, requiring only four precision rollers to guide the tape. 2.
Figure 2-12 Helical Scan Tape System must pull tape out of the cartridge and around a spinning read/write head. Acute wrap angles and recording-side contact reduce tape life. By contrast, the DLTtape head guide assembly is entirely different. It remains stationary. It consists of a series of six precision rollers.
Access door Leader Tape Supply reel Write Protect switch Drive access Figure 2-13 DLTtape Cartridge provides low-cost-per-gigabyte, high density data storage. Single-reel design eliminates wasted space. Single Reel Design The DLTtape media cartridge is unique in the midrange system market, in that it has only one reel. The take-up reel – the second reel – is in the DLTtape drive itself. This single-reel design leaves a great deal more space for tape inside the cartridge. (See Figure 2-13 and 2-14.
Figure 2-14 The Super DLTtape I Cartridge is a ruggedized design that includes an internal circular wall and ribbing, along with new wear-resistant materials to reduce the generation of debris. itself, and it is guided by the stationary HGA. It is inherently more stable, because much less movement is possible. When you look at a conventional two-reel 8mm cassette, it is obvious that the two reels take up a great deal of space, leaving less space for tape.
History of DLTtape Technology 3 In 1984, the Berlin Wall was still standing, and the real estate bust, Black Monday, recession, and the collapse of the minicomputer market were still years away. At home, Commodore 64 and Atari computers were selling well. On the IS front, the Apple Macintosh and the 80286 PC/AT were introduced and began to complicate life in the glass house. In 1984, Digital Equipment Corporation was on a roll, capturing midrange and mainframe market share with its networked minicomputers.
sette systems (DAT wasn’t out yet). Of course, the drive itself had to be made somewhat larger than most to accommodate the internal take-up reel. Dubbed the TK50, the new tape drive was capable of storing 94MB per cartridge. Using a ferrite read/write head, the TK50 recorded data in linear blocks along 22 tracks using two channels. The TK50’s read/write head actually contained two sets of read/write elements. One set was used when reading and writing forward and the other reading and writing backward.
Macintosh and its GUI operating system were growing in popularity, having entered through the back door of corporate graphics departments and in-house advertising groups. Need for Precision The TK70 wasn’t enough to quench the thirst for greater storage capacity and faster throughput speed in tape backup systems. Disk drive capacity was steadily increasing. Industry was becoming more dependent than ever on information systems technology.
Head Guide Assembly Probably the most important new feature introduced with the TF85 was the patented six-roller head guide assembly (HGA). This mechanism provides a gentle, solid path to precisely move the tape past the read/write head. This boomerang-shaped assembly consists of a forged aluminum base with six precision rollers fixed to it. The new HGA enabled the engineers to safely increase track density from 48 tracks to 128 tracks across the half-inch wide tape.
Head Drive Leader Take-up Reel Tach Assembly Figure 3-1 The Patented DLTtape Head Guide Assembly, first incorporated in the TF85 drive, is one of the keys to DLTtape reliability. Six precision rollers provide a gentle tape path for long tape life. In 1991, Windows 3.1 became a standard for PCs. “Mini” manufacturers industry-wide felt the pressure as companies discovered that a string of inexpensive PCs could be networked to do the same work that had once been the province of the minicomputer.
could store up to 50GB of uncompressed data using the DLT 2000 drive and eventually up to 100GB of uncompressed data using the DLT 4000 drive. Early in 1994, Digital began to gear up to sell DLT tape drives outside its normal user base. The SCSI-2 interface used by DLT drives was an industry standard that would allow almost any computer to work with the drives. At about this time, Digital renamed its disk and tape subsystem group Avastor.
cartridge. The new DLTtape system provided data transfer at 1.5MB/s (3MB/s compressed) and was fully read/write compatible with previous generations of DLTtape drives. Again, customer investments in DLTtape drives and media were preserved. Sales Growth Quantum sales rose to $3.5 billion for FY’95 on strong growth on all fronts. Quantum had evolved from its role as only a disk drive maker to a provider of mass-storage solutions.
Units, Drives Installed Units, Media Shipped 1,800,000 70,000,000 1,600,000 60,000,000 1,400,000 50,000,000 1,200,000 1,000,000 40,000,000 800,000 30,000,000 600,000 20,000,000 400,000 10,000,000 200,000 0 FY 97 FY 98 FY 99 FY 00 Q3FY 01 0 Source: Quantum Corporation Figure 3-2 The Installed Base of DLTtape systems has grown dramatically, with a projected total of over 1.5 million drives installed and over 55 million cartridges shipped to customers by the end of Q3, FY01.
benefit – investment protection: the DLT 8000 drive, which uses the same DLTtape IV tape cartridges as the DLT 7000 drive, is compatible with a very large percentage of all of the DLTtape media ever sold (some 55 million cartridges). DLTtape System Sales Growth At the end of FY '99, sales of DLTtape products hit $1.4 billion, and DLTtape products accounted for nearly 30 percent of Quantum’s sales.
technology. Volume production and first customer shipments began in Q1, 2001. These products address the individual storage needs of low-, mid-, and high-end customers in the mid-range data storage market. These new products include drives that deliver capacities of 110GB (uncompressed), and transfer rates of 11MB/s (uncompressed).
Why Customers Want DLTtape Systems 4 When Quantum bought DLT technology in 1994, sales of DLT products were running a modest 20,000 units per year. In just six years, DLTtape drive sales climbed to over 500,000 units a year. Why are so many people buying DLTtape systems? Some of the reasons have to do with big industry trends. Others have more to do with the basics of DLTtape technology itself.
the “birth of the server industry.” Of course, today’s servers look a great deal like yesterday’s minicomputers, and, instead of disappearing, this class of computers is growing very rapidly. These midrange servers support much larger disk storage than desktop systems. That means you need more backup capability – more capacity, more speed, and greater reliability. These backup needs are the strengths of the DLTtape system.
DLTtape drives installed, and over 55 million DLTtape cartridges in use worldwide. In the understated words of one user, “DLTtape technology is a well understood way to get a lot of data backed up.” Widely Available DLTtape systems are available from many sources. The list of OEMs who put DLTtape drives in their systems is impressive and growing. Almost all the leading vendors of mid-range computer systems or workstations sell DLTtape products, including Compaq, Dell, Hewlett-Packard, IBM, and Sun.
DLT 4000 DLT 7000 DLT1 DLT 8000 SDLT 220 Capacity (GB, native) 20 35 40 40 110 Data Rate (MB/s, native) 1.5 5.0 3.0 6.0 11.0 Bit Density (Kbpi) 82.
ical system administrator running a network backup application, more capacity per cartridge means less need to swap cartridges. More Reliable While we were researching this book, we talked to end users and network managers. Over and over again, they told us that they had switched to DLTtape backup because the systems they had been using just weren’t reliable enough anymore. Under the pressure of backing up big networks, 4mm and 8mm solutions just don’t cut it.
end server arena, some people mistakenly characterize DLTtape technology as expensive. That is simply not the case. One of the great things about the free market is that buyers usually figure out the best deals pretty quickly. Users want DLTtape technology because, as it turns out, in many applications, not only does it offer superior performance, but it’s also the least expensive way to get the job done. DLTtape technology isn’t the cheapest backup for desktop applications – yet. That’s still 4mm DAT.
technology. No other tape drive system packs as much data in a single cartridge as the DLTtape system; up to 110GB in native mode on a single Super DLTtape I cartridge. True Cost The true cost of backup isn’t in the drives and the media at all – it’s in the people and time it takes to meet your backup goals. If files are small and the windows of time are wide open, administrative costs probably aren’t even worth measuring. In these rare situations, the lowest initial cost solution works.
10,000 Media Recording Area (square inches) 8,000 6,000 4,000 2,000 0 DA T QI C-M C QI C-DC 8mm Half-inch DLTtape Figure 4-2 Half-inch DLTtape Media leaves plenty of room for capacity growth for future DLTtape drives. A single DLTtape cartridge has a tape area of over 10,000 square inches. the upper limits of their potential, DLTtape technology is just hitting its stride, with plenty of room to grow.
media ensures the highest track density available today. AMP uses durable metal powder technology for recording at very high densities. The back side of the AMP media contains specially formulated backcoating to receive the optical servo tracks, so customers can reserve the entire data-bearing side of the media for recording data and eliminate the need for pre-formatting. DLTtape System Compatibility In most cases, IS managers are reluctant to change backup technology.
Forward Write Cores Reverse Write Cores Reader Cores Figure 4-4 DLT 7000/DLT 8000 Read/Write Head tilts back and forth to record at highest data density, yet it can still read older formats by assuming vertical position shown here. tapes. You will never need most of them. But if you do need some old tapes from last year, or 5 years ago, or just last week, you would have a major problem if you had changed backup platforms. That is generally not the case with DLTtape technology.
Forward Tape Direction Reverse Tape Direction Figure 4-5 Symmetric Phase Recording (SPR), used in DLT 7000 and DLT 8000 drives, angles recording tracks to prevent cross-track interference and increase data density. Forward Tape Direction Reverse Tape Direction Figure 4-6 DLT 7000/8000 Head Positioned to read DLTtape cartridge recorded on an older DLTtape drive, providing compatibility and data interchange. QUANTUM DLTtape HANDBOOK 4.
Tape direction when in this orientation Tape direction when in this orientation Figure 4-7 The Super DLTtape Backward Read Compatible Head Assembly tilts to read DLTtape IV cartridges recorded on DLT 7000 and DLT 8000 drives, which use Symmetric Phase Recording (SPR). The DLT1 drive uses DLTtape IV media, so DLT1 drives can read any DLTtape IV cartridges recorded on DLT 4000 drives. And, of course, DLTtape IV cartridges recorded on DLT1 drives can be read by DLT 4000 drives and by SDLT 220 drives.
Reliability: The Heart of the DLTtape System 5 There is nothing more frustrating (or costly) than attempting to restore a file or directory, only to discover it can’t be done because of errors or worn out tape. An inexpensive tape drive suddenly loses its appeal when a project manager is upset about a corrupted file that can’t be restored. It doesn’t matter who deleted the original version; it’s the IS manager’s fault.
up applications. In this chapter, we will take a look at the DLTtape system features that make it the most reliable mid-range backup system on the market today. Unlike drives based on consumer video or audio recording technology, such as 8mm and DAT, DLTtape systems were designed from the start for intensive data storage use in mid-range and high end environments. DLTtape drive components and media work in harmony to provide the fastest, most reliable, highest capacity tape drives in the industry.
Head Drive Leader Take-up Reel Tach Assembly Figure 5-1 Patented Head Guide Assembly (HGA) used in the DLT 4000, DLT 7000, and DLT 8000 drives provides a rock solid tape path for industry-leading reliability and accuracy. Head Drive Leader Head Guide Rollers Take-up Reel Figure 5-2 The Super DLTtape Head Guide Assembly is a refined version of the DLTtape Head Guide Assembly. It incorporates only four rollers, further reducing contact and tape wear. QUANTUM DLTtape HANDBOOK 5.
that stress the tape. DLTtape rollers are large and are arranged in a gentle arc along the HGA. This roller arrangement results in much less wear than in helical scan system. When a DLTtape cartridge is inserted into the drive, it is automatically locked into position. A patented buckling mechanism pulls the DLTtape media from its cartridge. Unlike 8mm and other cartridge tape systems, DLTtape cartridges have a supply reel, but no take-up reel.
Figure 5-4 Super DLTtape System Tape Path is even simpler than that of the DLTtape drive, requiring only four precision rollers to guide the tape. to step up and down from track to track or, in the case of the DLT 7000 and DLT 8000 drives, to tilt forward and back. The drive’s head is gently contoured to minimize tape deflection at the contact point. Low tape tension, a non-rotating head, and special wearresistant tape coating give DLTtape drives industry-leading head life.
tachometer also helps the system keep track of how much tape is wound onto each reel and adjusts the speed of the two motors accordingly. Each time a cartridge is loaded, the drive calculates and sets the minimum tension required to achieve high-quality, consistent read/write signals. This calibration system maintains optimal-contact recording and helps extend the operational life of the drive.
outrigger islands help wipe contaminants such as dust from the tape as it passes. Like tiny stationary squeegees, these non-energized islands continuously clean the DLTtape media, ensuring proper tape/head contact, and data integrity. A low-stress tape path, contoured head, and self-cleaning design team up to provide up to 1,000,000 tape passes. All DLTtape cartridges provide a shelf life of up to 30 years with just a five percent loss in magnetic strength.
Channel 1 1 5 9 7 11 ECC2 Channel 2 2 6 10 13 12 ECC3 Channel 3 3 7 11 14 16 ECC4 Channel 4 4 8 12 15 ECC1 ECC4 Direction of Tape Motion Figure 5-6 Parallel Channel Architecture on all DLTtape drives (DLT 8000 shown here) automatically transfers data from bad blocks to parallel channels for "on the fly" data recovery. Adaptive Cache Buffering DLTtape drives feature adaptive cache buffering, which helps reduce stops and starts, reducing drive wear and tear.
cent usage. In fact, even at 100 percent duty-cycle, DLTtape drives are rated at up to 250,000 hours Mean Time Between Failures (MTBF). Even when compared to a competing drive offering the same MTBF, DLTtape drives are the clear winners, because we have calculated MTBF assuming 100 percent usage. In practice, few drives will actually be subjected to non-stop operation. But, it’s nice to know you could run your DLTtape drive continuously if you needed to without worry of premature failure or data loss.
Demystifying Tape Drive Specs 6 Specifications can be stated in different formats, using different terms, which may or may not mean the same thing. And sometimes two different vendors will use the same term, but will base their use of the term on very different standards. For example, identical MTBF (Mean Time Between Failures) figures can be based on very different assumptions for duty cycle or operating conditions (temperature and humidity).
DLT 4000 DLT 7000 DLT1 DLT 8000 SDLT 220 Native Capacity 20GB 35GB 40GB 40GB 110GB Compressed Capacity (2:1) 40GB 70GB 80GB 80GB 220GB Native Transfer Rate 1.
very effectively, as can big graphics files. Other material, like tables, for example, doesn’t compress much at all. Files that have already been compressed may even get bigger if you try to compress them. The bottom line is that compression may or may not be relevant to your application, depending on the kind of data you deal with. Just make sure that you compare native-to-native, or compressed-toequally-compressed figures.
Load Time Load time is the time from the moment you insert a cartridge into the drive, until the cartridge is ready to read or write the data. When discussing the DLTtape system, competitors often make the accurate statement that the load time spec for a DLTtape cartridge is approximately one minute. While accurate, that statement is not complete. Load time for a DLTtape cartridge is approximately one minute, but only for the first time a blank cartridge is loaded.
turer claims that, on average, this unit will run for 10,000 hours (or about 416 days) before it will break down and stop working. The bottom line is this: the DLTtape system, with its patented head design, lowtension-tape contact, simple tape path, and stationery heads, has an inherently more reliable design than that of competitive products. Reliability and Environment Another spec to look at when you compare reliability is environmental operating conditions.
Figure 6-2 A Gentle Tape Path in all DLTtape drives reduces stress and wear resulting in industry-leading tape life of up to 1,000,000 passes. ally use far lower figures. A DLTtape drive lays down data in a series of parallel tracks that run the length of the tape. As a result, it takes multiple passes to read or write the same amount of data on DLTtape media that should be read or written in a single pass on competitive drives.
than for a drive with rotating heads. DLTtape media is more durable than other types of media by a very wide margin. Data Integrity – Error Correction The important figure in terms of data integrity is the uncorrected bit error rate, sometimes referred to as the hard error rate. Uncorrected bit error rate is the number of erroneous bits that cannot be corrected by error correction algorithms. For DLTtape and Super DLTtape drives, we have calculated an uncorrected bit error rate of one bit in 1017 bits.
centage of recorded data, and in larger blocks (measured in number of consecutive bytes) to prevent data loss. During write operations, the DLTtape drive assures that the data written is correct by performing a read after write. If an error is detected, the drive rewrites the data block (see Figure 6-3) further down the tape until the read-after-write check validates that the block is now correct. In addition, the drive records powerful ReedSolomon ECC blocks on tape.
DLTtape Media 7 A DLTtape cartridge is 4.16 inches wide, by 4.15 inches deep, by 1 inch high. It weighs between 7.7 and 7.85 ounces, depending on specific model. A DLTtape cartridge holds between 1,200 and 1,828 feet of half-inch wide metal particle recording tape. A specially designed 18-inch leader is at the front end of the tape. The tape cartridge enclosure includes a drive gear that engages with the DLTtape drive, and a panel that opens to provide access to the tape.
Native Transfer Rate (read on DLT 8000) Native Transfer Rate (read on SDLT 220) NA 1.5MB/s NA 1.5MB/s 1.5MB/s 1.5MB/s 1.5MB/s 1.5MB/s 5MB/s NA 5MB/s 3.5MB/s 40GB 1.5MB/s NA 3MB/s NA 3MB/s 40GB 1.5MB/s 5MB/s NA 6MB/s 4MB/s NA NA NA NA 11MB/s Tape Type (recorded on drive type) Native Capacity Native Transfer Rate (read on DLT 4000) Native Transfer Rate (read on DLT 7000) DLTtape IIIXT (recorded on DLT 2000XT) 15GB 1.5MB/s 1.
Access door Tape Leader Supply reel Write Protect switch Drive access Figure 7-2 One-Reel Design of DLTtape Cartridge eliminates the wasted space found in competing technologies and offers the highest data density on the market. The one-reel design of the DLTtape cartridge offers two major benefits. First, the DLTtape cartridge has no wasted space. It is packed full of tape, which means more capacity per cartridge.
Super DLTtape I Tape Cartridge Leader Super DLTtape Drive Leader DLTtape IV Tape Cartridge Leader Figure 7-3 The Super DLTtape Positive Leader Link supports linking of both DLTtape IV and Super DLTtape I cartridges. On Super DLTtape I cartridges, a unique new buckling system increases cartridge life and supports heavy-duty-cycle environments. (See Figure 7-3.) A solid metal pin attached to the drive leader links with molded clips that are permanently attached to the tape leader inside the cartridge.
SCRATCH AREA Set Write Currents ■ Determine optimal tape Tension ■ Individually adjust Write Current for each write gap ■ DIRECTORY AREA ■ Used for Fast Search EOT HOLE ■ Physical End of Tape Leader Splice Scratch Area Calibration Directory Area Area DATA CALIBRATION AREA BOT HOLE ■ Position ■ Physical head in vertical Beginning of Tape ■ Determine optimal azimuth position (DLT 7000) ■ Line up data tracks with cal tracks for Interchange ■ Density Detection Figure 7-4 DLTtape Media Format
DLTtape IIIXT DLTtape IV DLTtape III Super DLTtape I Figure 7-5 DLTtape Cartridges Are Color Coded for easy identification. DLTtape IIIXT cartridge has a native capacity of 15GB, and the DLTtape IV cartridge has a native capacity of 35 or 40GB. Super DLTtape I cartridges have a capacity of 110GB. What accounts for the difference in capacity between cartridges? There are several factors. First and most obvious is tape length.
10,000 Media Recording Area (square inches) 8,000 6,000 4,000 2,000 0 DA T QI C-M C QI C-DC 8mm Half-inch DLTtape Figure 7-6 Half-inch DLTtape Media leaves plenty of room for capacity growth for future DLTtape drives. A single DLTtape cartridge has a tape area of over 10,000 square inches. tapes (see Figure 7-7). Smaller particle size translates into the ability to pack more data tracks into the same half-inch wide tape. The higher-capacity DLTtape IV media also has different magnetic properties.
DLTtape III Magnetic Layer (Metal Particle) DLTtape IV Magnetic Layer (Metal Particle) Non Magnetic Layer (Titan Fine Particle) Base Film Base Film Super DLTtape I Magnetic Layer (Metal Powder) Under Layer Base Layer Back Coat with Servo Guides Figure 7-7 DLTtape III, DLTtape IV and Super DLTtape I Media Compared. Finer magnetic particles used on DLTtape IV media allow for higher data density, while the Advanced Metal Powder Media in Super DLTtape I media supports even higher density.
media. That quality has been proven by over 55 million DLTtape cartridges sold. These cartridges provide unsurpassed durability and reliability. They are rated at one million tape passes, and have an archival life expectancy of 30 years. CompacTape CompacTape was the name used for DLTtape media until 1996, when the name was changed to “DLTtape.” The change was made in order to make it easier for users to associate the correct media with their DLTtape drives.
Automation 8 According to a report from the market research firm IDC, the overall market for tape libraries is growing at an annual rate of 25 percent, while the market for DLTtape system-based libraries is growing at a rate of 35 percent. Analysts estimate that 1999 shipments of DLTtape-based tape autoloaders and libraries were 79,000 units, and will grow to over 250,000 units by 2003.
Worldwide Tape Automation Units Shipped 500,000 450,000 4 mm 8 mm 400,000 350,000 300,000 DLTtape* 250,000 200,000 150,000 100,000 50,000 0 LTO Ultrium Half Inch 1998 1999 Source: IDC June 2000 2000 2001 2002 2003 2004 *Including Benchmark’s DLT1 tape drive and future generations of compatible DLTtape drives. Figure 8-1 The DLTtape System Is the Overwhelming Choice among high-performance tape systems for automated libraries.
is the need to gain control of their rapidly expanding information storage resources. The world of the mainframe is probably gone forever. We now live in a world of distributed computing resources, heterogeneous system environments, pervasive Internet/Intranet influence, and sky’s-the-limit application size. The growing demand for more storage capacity among UNIX and PC LANs, coupled with shrinking backup windows, has led to a strong move toward recentralization of network computing power.
Growth of SANs and NAS One of the major factors in the continuing growth of the market for DLTtape-technology-based automated libraries will be the emergence of new storage models, including Storage Area Networks (SANs) and Network Attached Storage (NAS). Both of these storage concepts place increased emphasis on the need for high-performance, high-capacity backup and recovery capabilities. Those capabilities are being delivered by DLTtape libraries. (See Figure 8-2.
Figure 8-2 Evolution of Storage Management QUANTUM DLTtape HANDBOOK 8.
cost and with little management overhead. NAS, however, is not the same as backup. In fact, by making it possible to easily expand storage, NAS creates the need for expanded backup capacity. This is where DLTtape-based libraries fit in the NAS concept. In a typical configuration, a DLTtape library is attached to a server designated as the backup server. DLTtape libraries offer the speed, capacity, and scalability to support the growing NAS capability, while delivering reliable, automated backup.
Improved data security and availability. Backups become automatic, and backups are never missed. Data is secure and available at a moment’s notice. Seamless disaster recovery. With a two-drive system, a complete copy of a full backup can be made at the same time the primary copy is running. Disaster recovery becomes almost effortless. It is still necessary to test disaster recovery procedures on a regular basis, but you’ll know the data is secure.
How To Buy a Tape Automation System What should you look for in a tape automation system? As in buying a standalone tape drive, it’s best to begin with an evaluation of your current situation and your future needs.
Controller card Multi-cartridge magazine Robotic cartridge handler Power supply Barcode reader DLTtape cartridges DLTtape drives Housing Figure 8-3 "Typical" DLTtape System-Based Library Design shows DLTtape drives, robotic cartridge handling system, DLTtape cartridges, and controller mechanism. to be loaded individually into storage slots inside the library. Important Note: be wary of manufacturers’ total capacity claims.
Each library maker has their own tape handling mechanism. Some of the different mechanisms you’ll find include robotic arms, elevators, and carousels. Some libraries are equipped with multiple mechanisms. Another feature to look for in larger libraries is a “mailbox.” This is a slot or compartment at the front of the system that allows the operator to load one or more tapes without opening the main door and interrupting library activity.
Protective housing. The higher the capacity of the library, the larger the housing. From table top to room size, tape libraries come in every shape and size. If you buy an expandable library system, you should consider future space requirement when locating the library. Some libraries expand by stacking one on top of the other. Others are only expandable from side to side. Bar code reader.
By starting with DLTtape system-based automation systems, you know you’re getting rock-solid drives at the heart of the system, drives that are renowned for reliable, error-free operation. Once you’ve made the decision to select a DLTtape-based system, you can focus on the automation vendor, robotics reliability, the number of drives available, and the total capacity.
management and backup are becoming increasingly popular. Storage Area Networks give users anywhere on the network access to a large, centralized pool of storage resources sitting on their own high-speed network – and backed up by DLTtape libraries.Tape automation systems and new versions of backup software make this a viable strategy. The use of high speed network backbones enable IS managers to centralize file services without crippling network performance.
Horizontal Applications 9 No matter what business you’re in, or what industry-specific applications you may use, you almost certainly need data backup and archiving. These are fundamental applications in the data storage world, and this is where the DLTtape system is used most. In fact, nearly 90 percent of all DLTtape systems sold are used for backup and archiving.
HSM Near On-line Archiving Other: Data Collection Remote Vaulting Image/Video Backup and Restore Figure 9-1 Current DLTtape System Applications include traditional applications such as backup and archiving, as well as newer applications like HSM. technology. What follows is a look at the leading uses of the DLTtape system and the data management issues you may encounter when implementing them (see Figure 9-1).
protective spot for a period of time. Some companies, especially those required by law to maintain historical records such as insurance companies and banks, archive data to special vaults or storage sites specially designed to protect valuable records. File-by-file vs. Image Backups There are two basic forms of backup: file-by-file and image backup. File-by-file backups take much longer than image backups, because the backup system must request each file from the operating system.
of the data must be weighed against the cost of the system required to back it up. If the data is important, the cost in system performance and the cost of acquisition can be more than justified. DLTtape systems are ideal for real-time backup because they minimize the drag on system performance caused by continuous updates. Near On-Line Storage Near on-line storage is similar to hierarchical storage management.
as if it were a disk. Only a handful of companies provide this type of software application, and it’s typically used with desktop systems and not with servers or network access. DLTtape systems are typically not used in this type of application. Most tape-as-disk systems use lower end, inexpensive tape drives. Hierarchical Storage Management (HSM) Hierarchical storage management is a multi-level approach to providing access to little-used, but critical information (see Figure 9-2).
optical disk front ends that act as a high speed cache. The HSM management software attempts to “anticipate” the file usage needs of your users, based on criteria you set. Files may be moved to progressively deeper storage based on the date they were last used or the importance of the files. Newer or more critical files may be kept on the HSM’s hard disk cache for fast recall. As these files age, they may be moved off to storage in the system’s tape library.
Surprisingly, HSM systems are not proliferating as rapidly as originally expected. This is due in large part to the drop in price and increased capacity of today’s disk drives. In addition, many library and autoloader tape systems can perform many of the functions that are typically associated with HSM systems. Libraries and autoloaders can provide vast amounts of near on-line storage, unattended access for users, and fast backups.
backup capacity, it can have a significant impact on overall performance. The system incorporates software algorithms that select which files are backed up to the disk portion of the backup space. In general, the most active files are backed up to disk. Then as these files become less active, they are migrated to tape backup.
RAIT systems work in essentially the same way as RAID. RAIT is ranked by six increasing levels of security and capability from Level 0 to Level 5. For example, Level 1 RAIT provides disk mirroring in which your data is written to two drives simultaneously. Each drive contains the same data. This is known as disk mirroring or disk duplexing. Should a drive fail for any reason, the other drive continues operation unaffected.
11 12 1 2 10 3 9 4 8 7 6 5 Protected Netware servers 11:05:00 AM 11:05:15 AM Server failure reported. Back-up and recovery server stands in for down server. Broken server 11 12 1 2 10 3 9 4 8 7 6 5 Back-up and recovery server with DLTtape autoloader Figure 9-4 New Backup And Recovery Systems provide real-time backup and recovery features. Every business and organization should have some provision for business continuity should a calamity strike.
Library Management This class of software application allows your network to access information stored on tape libraries and autoloaders. Library management applications can either be used as stand alone systems that allow the operator to move cartridges around, take inventory and find out what’s on various tapes, or they can be used as a layer of software between another application and the library.
Vertical Market Applications 10 DLTtape System Records Moments of Creation CLEO is a 1,200 ton detection apparatus at the business end of the half-mile-diameter linear accelerator buried beneath the athletic fields at Cornell University in Ithaca, New York. CLEO’s 100,000 detectors surround the points where electrons and their anti-particles, positrons, collide and annihilate each other. The resulting flash of energy unleashes new, sometimes exotic, matter.
8mm Couldn’t Take It LNS selected DLTtape systems because of the technology’s reputation for reliability in heavy-duty-cycle environments. Twenty-five out of the 30 DLTtape drives used by LNS are running at 75 percent duty cycle or greater, every day. At that rate of usage, the research center’s 8mm drives lasted only two months. At last count, the center’s DLTtape systems had been running for over 18 months with no problems! Another advantage offered by DLTtape systems was time saved in tape interchange.
• E-commerce. • Internet/Intranet. • Data mining. • Graphic arts. • CAE/CAD/CAM. • Multimedia. • Publishing. • Data acquisition. • DVD mastering. • Video-on-demand. • Digital nonlinear video editing. • Medical imaging. • Disaster recovery. • Video distribution.
ways. Probably the most common difference is the standalone nature of many vertical applications. While these special-purpose systems may be linked to a network system, they often don’t rely directly on the network for their operation. The special-purpose application is usually substantial enough to require its own backup system, rather than share a networked system. Another characteristic common to many vertical DLTtape applications is the use of graphics.
In film and video editing and special effects creation, it is critical for editors to be able to move jobs quickly and safely on and off their workstations. In many organizations, each editing workstation has a dedicated DLTtape drive for near on-line storage. The introduction of Super DLTtape drives allows editors to move jobs on and off their workstations faster, thus eliminating down time, and lets them manage even larger files more efficiently, again saving time.
capacity, room for growth, speed, and (most importantly) reliability to support the e-commerce mission. DLTtape technology fits into the mission-critical e-commerce storage environment at multiple levels. For example, a business-to-business equipment auction house uses server-attached DLTtape drives for conventional backup of its Web-based and live auction data. The firm’s IT manager explains that, “Loss of data would translate into a huge loss of business.
pages that have disappeared from the Web, leaving behind “This Page Not Found” messages. These “lost” pages have enormous potential value for academic and industry research – value protected by DLTtape technology. Working in the Data Mines Data mining is another good example of the kind of vertical application we’re talking about. It usually involves taking huge blocks of information that the organization has had for years – typically customer account information – and finding new ways to look at it.
Medical Imaging An increasing number of hospitals, laboratories, doctors, and medical research centers are relying on digital imaging to help speed diagnosis, save money, improve treatment quality, and accelerate medical training. Images from diagnostic tools such as CAT scanners, MRI, echocardiograms, and X-rays are increasingly being stored digitally and used either locally or in remote locations. A single 30-second echocardiogram, for instance, can take up to 10GB of disk or tape storage.
When the developers at Metrum-Datatape Incorporated went looking for an off-the-shelf tape drive to incorporate in their Multi-Application Recorder/Reproducer (MARS-II), they quickly discovered that the DLTtape system offered exactly what they needed. MARS-II systems are used to record critical flight and instrument data during testing of prototype military aircraft, avionics, and weapons.
That’s where DLTtape technology comes in. Ontario-based Avax International specializes in unattended tape backup and data interchange solutions. The firm supplies DLTtape systems for a wide range of applications, including oil and gas exploration. In the words of Andrew Senior, an applications engineer at Avax, “DLTtape systems can record a lot of data fast.” Another important geophysical application is transcribing data from old tapes to DLTtape cartridges.
Today, new disaster recovery schemes are emerging that place greater importance on keeping a backup database up-to-date at all times. For instance, electronic vaulting in the form of data mirroring or shadowing reduces the recovery time for mission critical applications. Shadowing and mirroring maintains an exact copy of the primary database at a remote site.
Digital Publishing The publishing industry is going digital as fast as it can. Digital presses, digital printing plate production, digital proofing, digital files, digital images…digital everything! Digital publishing reduces preparation time, saves on labor, reduces inventories, and, in the case of the Web and CD-ROM, can even eliminate paper altogether. DLTtape systems are ideal for digital publishing applications.
Backup for “Road Warriors” Today’s business “road warriors” succeed or fail based on the information they carry in their portable computers. A stolen or damaged laptop, or a lost file, can mean failure if the data is not backed up. Connected Corporation offers a solution: intelligent, hands-off, online data protection and real-time recovery for Windows-based PCs. Every day, thousands of Windows NT 4.
Eight Compaq tape libraries handle all server backup, including all remote sites, over high-speed T1 lines. Full server backups are done weekly; differential backups are performed nightly. Law Firm Backs Up Time and Billing Data Few things are more important to a law firm than the integrity of their time and billing records. The international law firm of Cozen and O’Connor has been in business for 20 years and is headquartered in Philadelphia, with 12 offices across the country.
One example of how the DLTtape system is being used in a multimedia application is at a developer and publisher of computer entertainment software. These games are intricate blends of music, sound effects, computer graphics, photographs, live action, dialogue, and other elements. Each video game product represents many months of intense development effort. Game development cycles often overlap, so that several games may be in development simultaneously.
ongoing backup. Typically, the editor will work on one job for a period of time, perhaps several hours. When he or she finishes work on that project – completes a new scene, or completes a set of revisions, or simply needs to get on something with a hotter deadline – the editor doesn’t simply close that file and open a new one. That won’t work. The files, the individual projects, are usually so big that you can only have one active at a time.
demand (VOD) service right now on a test-market basis. VOD services use cable to provide homes with an array of services, including home shopping, interactive games, on-line banking, and video on demand. The DLTtape system provides the high capacity, fast throughput and total reliability that are a must for video on demand applications. The DLTtape system can help the VOD service provider deliver much of the programming and promotional material that appears on the network.
back up digital media.” Avid lists a number of important reasons why its customers should consider DLTtape systems, including: Protection from data loss. By backing up digital source footage, users can go back to the digitized media, modify projects, or access clips for new programs. In many Avid resolutions, it’s faster to restore from a DLTtape backup than to redigitize. Archiving. Unlike many magnetic tapes, DLTtape media can be stored for years without fear of media degradation. Fast project turnaround.
DLTtape System Technology Compared 11 It would be easy to say there's no comparison to DLTtape system technology – it’s the best! But, nothing is that simple. Sure, DLTtape products are fast, reliable, and offer industry-leading capacity and speed. Depending on your application, DLTtape technology may very well be your best choice in a tape backup system. However, to make the right choice, you need to know more about the leading backup options.
• How important is backup system reliability? • What will media cost (cost per gigabyte)? • Is the backup system supported by third-party software? • Is there a clear growth path for my backup system? These are just some of the factors you should consider as you embark on your quest for the perfect backup solution.
Figure 11-2 Tape Path Is a Key reason for DLTtape media’s industry-leading reliability, long life, and accuracy. Six precision rollers guide tape to internal take-up reel; the Super DLTtape drive uses four rollers. from the cartridge along a gently curving path (see Figure 11-2) past the write-read-write head to the take-up reel.
Figure 11-3 Typical Helical Scan Tape System must pull tape out of the cartridge and around a spinning read/write head. Acute wrap angles and recording-side contact reduce tape life. and records to the end. The drive then steps the head to the next track, reverses direction and records back to the beginning of the tape, and so on. One of the main reasons DLTtape drives achieve such high data transfer rates is because data is written using multiple channels.
data accuracy. These include parity, multi-layer cyclical redundancy code (CRC), error detection code (EDC) and custom Reed-Solomon Error Correction Code (see Chapters 5 and 6 to learn more). An additional advantage provided by the DLT 7000 and DLT 8000 drives is Symmetric Phase Recording (SPR). Using SPR technology, adjacent data tracks are recorded using alternating head angles. The resulting herringbone pattern eliminates cross-talk interference and the need for guard bands between tracks.
of the DLTtape drives, with even less contact between the tape media and the rollers. The dual motor system in Super DLTtape drives is very similar to that used in the DLTtape drives. Super DLTtape drives record data in a serpentine linear format, just like DLTtape drives, but use eight-channel recording, versus four channels for the DLT 7000 and DLT 8000 drives. Super DLTtape technology employs the same Parallel Channel Architecture as previous DLTtape drives.
Helical Scan Systems The next two backup systems we’ll discuss are 4mm DAT (digital audio tape) and 8mm tape. Both of these systems are based on helical scan technology developed in the early days of television to store video images. This is virtually the same technology used in your home VCR. With QIC and DLTtape systems, the tape is drawn rapidly past a fixed read/write head. With helical scan systems, both the tape and head move.
Sony AIT-2 Sony's AIT-2 drive is a high-performance 8mm helical scan drive offering a native capacity of 50GB and a native transfer rate of 6MB/sec. Important features of the AIT-2 technology include its Memory In Cartridge (MIC) feature, which stores data on the contents and usage history of the cartridge in a chip that can be read by a library automation device. It is important to note that, while AIT-2 is an 8mm technology, it is not compatible with previous generations of 8mm drives.
effort. Such efforts can very easily get bogged down by conflict between the competing interests of the partners. Second, unlike Super DLTtape systems, Mammoth-2, or AIT-2, there is no installed base of Ultrium products. Therefore, any user who decides to move to the Ultrium technology must either maintain their previous technology in order to be able to access archived data, or go through the process of converting all their archived data to a new format, or simply abandon archived data.
that any new QIC drive you buy is compatible with your existing tape cartridges. Incompatibility among QIC drives and tape formats is a real problem that must be considered when purchasing this type of system. Like the DLTtape system, QIC systems use a serpentine recording method. Until recently, QIC systems used a single channel for read/writes. One vendor has introduced a multi-channel QIC system that offers a capacity of 13GB.
Write once, read many (WORM) drives have been available for many years and are most often used to provide a permanent record for critical information, or are used in optical jukeboxes in hierarchical storage management (HSM) systems. Law firms, for instance, often use WORM drives to store important documents and court records. WORM media has a shelf life of at least 30 years. A standard CD format version of the WORM drive is known as a CD-R for CD recordable.
Magneto-optical (MO) drives use a combination laser/magnetic head to achieve higher storage capacities than PD drives. However, higher capacity comes at the expense of compatibility with standard CD drives. MO disks can only be read by other MO drives. The highest capacity MO drive on the market today offers 4.6GB of storage, hardly sufficient for serious storage applications. MO drives are slow during write operations because they must erase each disk sector before new data can be written.
Evaluating the Cost of a DLTtape Backup Solution 12 What does DLTtape system backup cost? We could answer by showing you a price list, but that isn’t really an answer at all. If you are considering using a DLTtape system for backup, then you are in the market for a serious backup system. Serious backup isn’t just buying a box. It is a mission critical function. You need a systematic approach, and you need to make a significant and continuing investment in backup. The box is just the beginning.
If you’re dealing in megabytes, you probably do not need an industrial-strength solution. You are probably well covered by a desktop solution using 4mm DAT tape that costs a few hundred dollars. However, once your volume reaches gigabytes, you should consider a more robust solution, like a DLTtape system. If you must deal with tens or hundreds of gigabytes, or terabytes, you should consider a DLTtape library or autoloader.
Media Costs ($/GB) $6.0 5.0 DLT 4000 4.0 3.0 DLT 7000 DLT1 DLT 8000 2.0 SDLT 220 1.0 20 40 60 80 100 120 Native Capacity (GB) Figure 12-1 Cost per Gigabyte of Storage is a function of media capacity. High-capacity DLTtape IV and Super DLTtape I cartridges deliver the lowest dollars-per-gigabyte cost. What Does Media Cost? Media prices fluctuate.
last week’s backups off-site, so that would mean a total of investment of 20 DLTtape cartridges. Archiving data presents a very different need. When you are consuming tapes on an ongoing basis, rather than rotating the same tapes through the system, media costs are higher. This is another case in which the high capacity DLTtape cartridges are more economical than lower capacity cassettes. In fact, the difference in cost over the long run can be dramatic.
DLTtape drives in the world – and can deliver the maximum performance possible for every one of those drives. For users, that means they do not need to go to the great expense of transferring all their older tapes to new media just to make them readable. And it means that users with a mix of DLTtape drives can buy a single type of cartridge to support all their stand-alone and library drives, reducing acquisition, stocking, and administrative costs.
Another DLTtape system user described his experience with labor costs in an application that required maintaining archives of client data. Using a 4mm DAT system, he recalls, he had reached the point at which he was tying up two staff members for a total of about 35 hours per week, simply swapping tapes and replacing failed drives. The lesson is clear: an inadequate, undersized, or insufficiently robust backup system can be a major expense, in terms of dollars and time, not to mention morale.
games (see Chapter 10 for more detail). Building a video game is a large, complex development project, and it is not uncommon to have a system error or, more commonly, a human error that can blow up a file. In that situation, you don’t want a whole team of developers sitting around for hours or even for many minutes waiting to restore the file from backup, so they can get on with their work. That’s when the high speed of a DLTtape system backup unit delivers hard cost benefits.
Platform Connectivity & Software Compatibility 13 For the vast majority of DLTtape system users, any issues of connectivity and compatibility have been worked out long before they turn on their new systems. That’s because most DLTtape systems are sold through OEMs such as Compaq, Dell, HP, IBM, and Sun. These platform vendors have already certified their systems to work with DLTtape drives through an in-depth qualification process described in this chapter.
(OEMs), value-added resellers (VARs), tape library makers, and independent software vendors (ISVs) achieve connectivity and compatibility with DLTtape systems and DLTtape libraries. Our connectivity and compatibility support generally falls into the following categories: • Platform Qualification Program and Web-based Platform Connectivity Matrix. Software Compatibility Program and Web-based Software • Compatibility Matrix. • Web-based Platform Solutions Guide and Application Notes.
form. This listing includes native applications such as tar backup, cpio, dd, Ftio and Fbackup. Examples of ISV partners include Computer Associates, Dantz, Legato, Seagate, Novastor, Microsoft, and many more. Host Attachment The first step to using a DLTtape drive or DLTtape-based tape library is to attach it to a host operating system by means of a tape driver.
the BRU commands; and HP uses fbackup and frestore. The Windows NT operating system comes with a native backup utility. Platform and Software Qualification Programs Every platform partner or ISV that wishes to either sell DLTtape drives or claim compatibility with DLTtape drives, must first go through a qualification process to ensure that the DLTtape drive will work with the target platform and any applications that may be associated with it.
time-to-market. By running some tests in parallel with Quantum, the customer saves time and expense. Up to 20 drives on several different types of host platforms are typically used during the RQT phase. RQT can last for up to ten weeks and is conducted late in the qualification cycle, after most issues have been resolved. RQT includes interchange testing, where tapes are written on one DLTtape drive and taken to another DLTtape drive to be read.
using a platform or application that has been qualified to work with a DLTtape drive, occasionally a customer will experience a problem in achieving expected performance. These types of cases are often the source for new application notes on our Web site. Quantum’s customer support engineers will try to simulate the customer’s problem in our test labs. The customer support engineer will pretend he or she is the customer unpacking the DLTtape drive for the first time and attempting to connect and operate it.
We are continually working with major ISVs to ensure support for current and future DLTtape products. We check ISV solutions to identify functional deficiencies, provide the ISV with performance tips and tuning, provide quantitative and qualitative feedback, and provide the latest firmware updates. Once an ISV solution is qualified (either by Quantum or the ISV, or both) on DLTtape drives, we encourage the ISV to add us to their Certified Device List as soon as possible.
Storage Management Software 14 Storage management software is a hot bed of evolutionary activity. A huge number of variables are in the mix, and new ones are popping every day. At the same time, the environment is changing very quickly, and the changing environment will have a lot to do with which variants emerge as successful species, and which disappear down evolutionary dead ends.
Finally, files are simply getting bigger. Not just the multimedia or imaging files, but even simple word processing files are getting larger and larger, adding layers of highlighting, tables, and mixed type fonts. Similarly, there was a time when an entire operating system would fit on a couple of floppy disks. Now, it takes a CDROM just to do a simple software upgrade. These trends have created a tremendous need for integrated, consistent storage management.
Figure 14-1 Evolution of Storage Management QUANTUM DLTtape HANDBOOK 14.
DLTtape System Technology And Storage Management As the shape of storage management software emerges, it’s clear that the DLTtape system is a good fit. Here are some of the strengths that make DLTtape technology the right foundation for enterprise storage management solutions. Capacity. The total size of the storage infrastructure in large organizations is growing at a tremendous pace. Storage capacity is absolutely essential, and the DLTtape system offers far more capacity than any other solution.
Breadth of product line. Quantum is taking advantage of the success of DLTtape technology by building an extensive family of DLTtape system products. In an enterprise storage strategy, that means you have a choice among multiple compatible building blocks, all using the same basic technology, but which you can deploy in different situations, depending on the exact needs of each piece of the storage hierarchy.
Firmware 15 Firmware is the “brains” behind the scenes in many of the products we take for granted. It's hard at work in your microwave oven, your calculator, your refrigerator, your digital watch, your kids’ electronic toys, your cell phone, your treadmill, and your car. Of course, firmware is also a crucial part of every piece of computer and telecommunications equipment in use today. Naturally, we’re interested here in how firmware works in your Quantum DLTtape system.
trol. In most cases, firmware interprets or translates commands from you, from applications, or from communication controllers and turns them into commands the machine or device can understand. Firmware And Your DLTtape System Every Quantum DLTtape system comes from the factory with firmware loaded in EEPROMs on the controller board mounted at the base of the drive. In the DLT 8000 drive, for example, there are approximately 400,000 lines of code written, primarily, in the C and C++ programming languages.
SCSI Interface SCSI (Small Computer System Interface) is at the heart of DLTtape drive control and communication. The SCSI interface is designed to be an industry standard for device control and communication. Among the SCSI commands supported by DLTtape firmware are ERASE, LOAD-UNLOAD, LOCATE, WRITE, READ, READ POSITION, and REWIND.
The flexibility provided by firmware enables Quantum to adapt DLTtape systems to meet almost any operating system or vendor requirements. In addition, when compared to hardware modifications, firmware changes usually take less development time and are less expensive to implement. It's important to note that nearly 99 percent of DLTtape firmware remains the same from system to system.
This innovative feature enables Quantum and its resellers to develop and issue new versions of drive firmware that enhance operation and product value. For instance, firmware is sometimes upgraded in the field to introduce an improved compression algorithm or to refine a particular SCSI command. In other cases, firmware upgrades may be required to help certain types of backup software to work with DLTtape drives.
downloaded to the host from Quantum’s bulletin board or corporate Web site. Looking Back While Moving Forward One of the key benefits of the DLTtape system is investment protection. Each new generation of DLTtape system has been compatible with previous generations. This means that your closet full of DLTtape IV cartridges recorded at 20GB on DLT 4000 drives or in DLTtape drive-equipped libraries are readable in the DLT 8000 and Super DLTtape drives. Again, this is possible thanks to firmware.
helping to implement these advanced features in future generations of DLTtape drives. Next, we'll look at learning how to use your DLTtape system. QUANTUM DLTtape HANDBOOK 15.
Using the DLTtape System 16 The DLTtape family of systems offers the highest reliability, capacity, and performance in the mid-range market today. For example, the DLT 8000 drive is rated at an MTBF (Mean Time Between Failures) of 250,000 hours – that’s over 28 years. DLT 8000 drive heads are self-cleaning and rated to last approximately 5.7 years at 100 percent duty-cycle. Our tapes are good for one million passes.
ing your DLTtape drive and media. These tips cover our standalone DLTtape systems. For operational information on other DLTtape automation systems and backup software, you should consult your system vendor directly or visit their Web site. DLTtape Media Do’s & Don’ts As the importance and volume of information continues to increase year after year, the need for reliable, long-term data storage grows with it.
tape. To reduce the chance of dropping cartridges, you should store them on their sides in their protective cases. Data Recovery. If a damaged tape contains important data, we recommend sending the tape to a qualified data recovery service, such as Ovation Data Services of Houston, Texas (www.ovationdata.com). Other recovery services can be found by searching the Internet. Stow Loose Labels. Every new DLTtape cartridge comes with a sheet of labels in its storage box.
Storage Requirements. As noted above, DLTtape media is ideal for long-term archiving, with a storage life of 30 years or more. To achieve its maximum shelf life, a DLTtape cartridge must be stored in its protective case on its side and kept within a reasonable temperature and humidity range. The ideal archival environment for storing DLTtape cartridges is at a temperature range of 64°F to 79°F and relative humidity of 40 to 60 percent. Avoid Temperature Extremes.
its own sophisticated computer system, including RAM, microprocessors, controllers, firmware, and data cache. Install your DLTtape drive in a clean area with an industrial-quality surge-protected power source. Be aware that many factors contribute to the overall performance you’ll experience with your DLTtape drive.
What’s The Hold-up? What if you install a DLTtape drive and you don’t get the performance you expect? Here are a few things to check. First, make sure your DLTtape drive is properly defined for the host system. It is common for a SCSI host to disable (Unbuffered Mode) the adaptive cache on the drive if it doesn’t recognize the product identification string returned by an inquiry command.
ed. Image files from a graphical program like Paint may compress at 4.5:1 or more, while binary files may compress at just 1.5:1. Data that has already been compressed or random data (such as encrypted data) may actually expand by about five percent if you attempt to compress it further. This can actually reduce drive throughput. Mixing Density. Your DLTtape system can easily mix compression ratios on a single tape. Compression will change on the fly depending on the input data.
www.quantum.com or www.DLTtape.com, or call your independent system vendor with any questions you may have about using your DLTtape drive, DLTtape-based tape automation system, or DLTtape cartridges. Next, we’ll look at the future of DLTtape system products – Super DLTtape technology. 16.
Super DLTtape:The Future of DLTtape Technology 17 Current Trends One reliable way to discern where IS and data storage management might be headed is to project present trends. Every current trend has a built-in momentum that will carry it forward. Some of the IS trends we see today that will continue to have an impact on the growth in popularity of DLTtape technology in the future include: • Growing network storage demands (some say total storage capacity is doubling every 12 to 18 months).
to solve the backup crisis, the DLTtape system will continue to be the system of choice for library vendors and end users alike. Big Iron In Server Clothing One trend that promises to continue for the foreseeable future is recentralization. In the past – before the personal computer – information management was handled by the “data processing” crew in the glass room with the raised floor. They handled data backup, application development, and access to information. Then the PC changed everything.
At the high end of the library market, modular systems that can be expanded with additional drives and tape slots will continue to offer cost-effective and scalable solutions. The fundamental features of the DLTtape system will continue to attract library makers. These manufacturers know that the very nature of library operation requires a drive that can withstand constant operation and countless loads and unloads without failing.
NATIVE TRANSFER RATE NATIVE CAPACITY Generation 4 SDLT 2400 (1.
tion starting in Q1, 2001. We believe this new Super DLTtape technology will become even more dominant than the DLTtape system is today. While today’s DLTtape technology is expanding its market share, the next-generation Super DLTtape products leapfrog all current and proposed competitive technologies. Our product development road map offers a path for customers to follow with confidence.
Seamless Transition DLTtape products, current and future, offer backward compatibility to the large and growing installed base of DLTtape systems. If you are running an IT operation, you will probably consider updating your backup strategy to take advantage of the dramatic increases in capacity and speed proposed for the next-generation technologies. However, your first question will probably be, “Can we do this without disruption.
flavors of standard UNIX over the years. Which has not prevented UNIX from working as an open system. On the other hand, Windows is proprietary. Yet, because it is also ubiquitous, Windows is clearly an industry standard. We believe that DLTtape technology, by virtue of its ubiquity, provides the advantages of an open industry standard: • It does not impose limits on the choices open to users. You can use the operating system, the hardware platform, and the applications, and utility software of your choice.
LGMR Technology The cornerstone of the Super DLTtape technology platform is its use of Laser Guided Magnetic Recording (LGMR). This unique technology application will produce an advanced scalable platform designed to meet an extraordinary range of storage requirements, and to support multiple generations of products.
Four key technologies contribute to the revolutionary capacity and performance LGMR brings to Super DLTtape technology. Those Quantum-patented technologies are: • Pivoting Optical Servo (POS) • Magneto-Resistive Cluster Heads (MRC) • A new, High-Efficiency PRML Channel • Advanced Metal Powder Media (AMP). Figure 17-2 LGMR Technology Increases Tape Capacity by increasing the number of recording tracks on the data-bearing side of the tape and servoing optically on the back side.
Figure 17-3 POS Technology Implements an optical servo on the unused back side of the media, allowing 100% of the data-bearing side to be used for data recording. sensitivity to outside influences, which allows the Super DLTtape system to achieve a track count with an order of magnitude increase over current DLTtape products.(See Figure 17-3.
Head motion Magneto-Resistive Cluster Heads Head motion Figure 17-4 Super DLTtape Read/Write Head features 8 channels. Very small Magneto-Resistive Cluster (MRC) Heads yield data transfer rates as high as 11MBs. New High-Efficiency PRML Channel A newer PRML channel improves on traditional PRML disk drive technology by bringing new levels of performance and capacity to LGMR technology and high-performance tape drives.
High Coercivity Magnetic Layer Under Layer Enhanced Base Film Layer Back Coat Layer with Servo Guides Figure 17-5 Advanced Metal Powder (AMP) Media supports high density data storage and embedded information for the Pivoting Optical Servo.
Super DLTtape I Tape Cartridge Leader Super DLTtape Drive Leader DLTtape IV Tape Cartridge Leader Figure 17-6 Positive Engagement Tape Leader Buckling Mechanism increases cartridge life and supports heavy duty-cycle, 7x24 environments, along with compatibility with DLTtape IV media. New, Rugged Media Cartridge The Super DLTtape I cartridge has a new, more rugged design for greater durability. (See Figure 17-7.
Increased structural ribbing Internal circular wall Figure 17-7 New, rugged cartridge design reduces the potential for damage, and wear resistant materials reduce debris generation. The modules include the best features of current DLTtape technology design and the breakthrough technologies that allow the Super DLTtape system to achieve its exceptional performance. Each module is optimized to perform a specific set of functions and is designed to interface with the other modules in a prescribed manner.
Data Control Module Tape Control Module Cartridge Tape Module Front Panel Module Electronic Interface Module Figure 17-8 The Modular Design of the Super DLTtape drives makes them easier to design, manufacture, and upgrade. central role of DLTtape technology in our customers’ storage strategies. We hope you’ve enjoyed this look into DLTtape technology. One thing is certain, the DLTtape system is the system to beat for a long time to come.
Appendix A Super DLTtape System Products: SDLT 220 Drive SDLT 220 For the mid-range server market, the SDLT 220 drive offers storage capacity of 110GB and data transfer rate of 11MB/sec. This model is designed to provide excellent data backup and archiving storage for mid-range UNIX and NT systems for use in larger corporate departments operating in networked or stand-alone application environments.
DLTtape System Products: DLT 8000 Drive DLT 8000 The Quantum DLT 8000 half-inch cartridge tape drive provides leadership in data storage and retrieval for demanding data backup, archiving, and near on-line storage applications for mid range systems. The tape drive features a native transfer rate of 6MB/s, with a native capacity of 40GB.
DLT1 Drive DLT1 The Quantum DLT1 half-inch tape drive is designed to provide high-capacity backup for small- to medium-size storage servers and workstations in cost-sensitive applications. The DLT1 tape drive offers a combination of 40GB native capacity per cartridge and a native transfer rate of 3MB/s.
DLT 4000 Drive DLT 4000 The Quantum DLT 4000 half-inch tape drive is designed for heavy duty-cycle computer applications in the lower to middle level of the tape drive market for mid-range systems. The DLT 4000 tape drive offers a combination of 20GB native capacity per cartridge and a native transfer rate of 1.5MB/s.
DLTtape Cartridges DLTtape III DLTtape IIIXT DLTtape IV Super DLTtape I The Quantum DLTtape family of half-inch cartridges, approved for use in all DLTtape system drives and autoloaders, delivers the highest capacity of any 5.25-inch cartridge – up to 220GB in compressed mode. To ensure accuracy, a patented tape leader ensures consistent tape motion, while a unique tape/reel locking mechanism prevents tape slack.
Glossary A Access. (v) Read, write, or update information on a storage medium, such as tape. (n) The operation of reading, writing, or updating stored information. Access time. The interval between the time a request for data is made by the system and the time the data is available from the drive. Advanced Metal Evaporated (AME). A type of tape media created by depositing a thin layer of magnetic material onto a base by means of evaporation. AME’s pure magnetic layer allows for high data density.
Advanced Servo Positioning (ASP). This closed-loop positioning system allows increased data density by continually adjusting the position of the tape drive’s read/write head to achieve the strongest signal strength. Allocation. The process of assigning particular areas of the media to particular data or instructions. Archiving. The removal of data from the computer system on to secondary storage media that is safely stored away.
Backup. A copy of a file, directory, or volume on a separate storage device from the original, for the purpose of retrieval in case the original is accidentally erased, damaged, or destroyed. Backup Window. The period of time used to back up critical databases and other information. With an increasing number of companies running 7x24 applications, the backup window in many cases is either shrinking or closed. Backward Compatibility.
Byte. The basic unit of computer memory, large enough to hold one character of alphanumeric data. Comprised of eight bits. See also bit. C CPU. Acronym for central processing unit. The microprocessor chip or group of chips that perform the bulk of data processing in a computer. CRC. Acronym for cyclic redundancy check. An error detection code that is recorded within each sector and is used to see whether parts of a string of data are missing or erroneous. Cache.
Compression. Encoding data to take up less storage space on magnetic tape. Compression is carried out in the host (software compression) or in the drive itself (hardware compression). Software compression speed is dependent on host processor power, whereas hardware compression gives optimum performance and is transparent to the user. Data transfer speed and total tape capacity are affected by the data compression achieved. Compression Algorithm.
Data Cartridge. The enclosed media cassette that is used to hold recording/restoral media. Data Compression. A process generated by either hardware or software that reduces the amount of storage space required to hold a particular block of data. Typical compression rates are 2:1 or 3:1 and allow approximately double and triple the data storage respectively. Data Integrity. The level of error-free storage of data. It is a key factor in the reliability of any technology. Data Interchange.
E ECC. Acronym for Error Correction Code. The incorporation of extra parity bits in transmitted data in order to detect errors that can be corrected by the controller. EDC. Acronym for Error Detection Code. DLTtape drives include a 16-bit EDC with every 4KB of user data. The EDC helps the drive detect and recover any errors that may occur. EEPROM. Acronym for electronically-erasable programmable read only memory. An integrated circuit memory chip that can store programs and data in a non-volatile state.
F FCI. Acronym for flux changes per inch. See also BPI. Faceplate. See bezel. Files. A distinct group of data blocks. File-by-File Backup. A recording method that records data a single file at a time as opposed to mirroring a tape or block of data. Firmware. Permanent or semi-permanent instructions and data programmed directly into the circuitry of programmable readonly memory or electronically-erasable programmable read-only memory chips. Used for controlling the operation of the computer or tape drive.
G Gigabyte (GB). A unit of measure consisting of one billion bytes (one thousand megabytes). H Half Height. Standard drive size equivalent to half the vertical space of a 5.25-inch drive. Hard Error. A data error that persists when the tape is reread, usually caused by defects in the physical surface. Head. The tiny electromagnetic coil and metal pole used to create and read back the magnetic patterns on the tape. Also known as the read/write head. Head Life.
I ISV. Acronym for independent software vendor. Image Backup. A backup option that takes a “snapshot” of an entire system by writing a volume image to tape sector-by-sector, rather than file-by-file. This method of backup is very fast and allows companies to backup critical information in a limited backup window. Interface. A hardware or software protocol, contained in the electronics of the tape controller and tape drive, that manages the exchange of data between the drive and computer.
K Kilobyte (KB). A unit of measure consisting of 1,024 bytes. L Lempel-Ziv Algorithm. A data compression technique used in all DLTtape drives. Named after Abraham Lempel and Jacob Ziv. Laser Guided Magnetic Recording (LGMR). The Super DLTtape data recording system. It employs a precision optical head mechanism (Pivoting Optical Servo) for accurate head tracking, along with magnetic heads for reading and writing data. Library System.
MTBF. Acronym for Mean Time Between Failures. Reliability rating indicating the expected failure rate of a product in power on hours (POH). Since manufacturers differ in the ways they determine the MTBF, comparisons of products should always take into account the MTBF calculation method. MTTR. Acronym for mean time to repair. The average time it takes to repair a drive that has failed for some reason.
Microsecond (µs). One millionth of a second (.000001 sec.). Millisecond (ms). One thousandth of a second (.001 sec.). Minicomputer. A somewhat out-of-date term used to describe a class of multi-user computer that was one notch below a mainframe system. Minicomputer popularity fell with the rise in popularity of the networked PC. Today’s server systems perform many of the functions that were once the domain of minicomputers. Mission Critical.
Overhead. Command overhead refers to the processing time required by the controller, host adapter, or drive prior to the execution of a command. Lower command overhead yields higher drive performance. Overwrite. To write data on top of existing data thus erasing the original data. P POH. Acronym for Power On Hours. The unit of measurement for Mean Time Between Failures (MTBF), expressed as the number of hours that the drive is powered on. See MTBF. PRML. See partial response, maximum likelihood.
Peripheral. A device added to a system as a complement to the basic CPU, such as a disk drive, tape drive, or printer. Petabyte. A unit of measure consisting of one quadrillion bytes (one billion megabytes). Pivoting Optical Servo (POS). An optically-assisted servo system designed for Super DLTtape for high-duty-cycle applications. Q QIC. Acronym for quarter inch cartridge. A tape storage subsystem that uses .25-inch-wide media. R RAM. Acronym for random access memory.
Read/Write Head. The mechanism by which data is recorded on to magnetic media in a tape or disk drive system. See Read After Write. Reed-Solomon Error Correction. An error correction technique based on research done by Irving Reed and Gustave Solomon at MIT’s Lincoln Laboratory in the 1960’s. First used to check the accuracy of data received from the Voyager spacecraft. Restore. To replace data on the hard drive from another media device. S SAN. See Storage Area Network SCSI.
Server. A powerful computer system with a large hard disk drive that serves the information access and communication needs of multiple users. Often servers are dedicated to a particular function such as Internet access, printing, file management, backup, and network communications. Servo Data. Magnetic markings written on the media that guide the read/write heads to the proper position. Shelf Life. The length of time that a tape can be stored without losing its magnetic strength.
Surface. The side of the tape that is coated with the magnetic material for recording data. Sustained Transfer Rate. The data transfer rate of a tape drive in native mode. For instance, the DLT 8000 has a sustained transfer rate of 6MB/s in native mode, and up to 12MB/s at 2:1 compression. Symmetric Phase Recording (SPR).
Thin Film. A type of coating allowing very thin layers of magnetic material used on tape drive read/write heads. Media with thin film surfaces can store greater amounts of data. Track. A linear or angled pattern of data written on a tape surface. DLTtape drives write information on multiple tracks simultaneously. Track-To-Track Seek Time. The time required for the read/write heads to move to an adjacent track. Transfer Rate. The rate at which the drive sends and receives data from the controller.
W Write Once, Read Many (WORM). An optical disk technology that allows the drive to store and read back data but prevents the drive from erasing information once it has been written. X, Y, Z No entries G.
Index A Advanced Metal Powder (AMP) Media, 4.8, 7.7, 7.8, 11.6, 17.9, 17.11, 17.12 Alexa Internet, 10.6 Alpha Workstation, 10.1 Application Notes, 16.1 Apple Macintosh, 3.1 Archiving, 1.13, 9.1, 9.2, 9.9, 10.9, 10.10, 10.18 Atari, 3.1 Autoloader, 1.12, 3.4, 4.3, 8.1, 8.3, 8.7, 9.11 Automation, 8.1, 8.2, 8.3, 8.6, 8.7, 8.8, 8.11, 8.12, 8.13, 14.5, 16.8, 17.1 Avax International, 10.10 Average Access (or Seek) Time, 6.3 Avid Technology, 4.3, 10.17, 10.18 B Backup, 1.1, 1.2, 1.3, 1.5, 1.6, 1.7, 1.8, 1.9, 1.
9.11, 10.2, 10.3, 10.4, 10.6, 10.7, 10.8, 10.10, 10.11, 10.13, 10.14, 10.15, 10.16, 10.17, 10.18, 11.1, 11.2, 11.9, 11.10, 11.11, 11.12, 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 13.1, 13.2, 13.3, 13.4, 13.6, 14.2, 15.5, 16.2, 16.5, 17.1, 17.2, 17.4, 17.6 Backward Compatibility, 1.11, 2.6, 3.10, 4.12, 7.2, 11.1, 16.7, 17.6, 17.12 Backup Management Software, 8.13 Bad Data Blocks, 11.4 Bar Code Reader, 8.11 Beginning of Tape (BOT), 7.5 Buckling Mechanism, 7.4, 11.6, 17.12, 17.13 C CAE/CAD/CAM, 1.7, 10.
Computer Associates, 13.3 Connected Corporation, 10.13 Cornell University, 10.1, 10.8 Corrupted File, 5.1 Cozen and O'Connor, 10.14 Cyclic Redundancy Code (CRC), 5.7, 11.5 D DAT, 1.3, 1.8, 3.2, 3.3, 3.7, 4.1, 4.7, 5.1, 5.2, 6.7, 10.11, 11.1, 11.7, 11.10, 12.2, 12.5, 12.6, 17.4 DDS, 1.8, 11.2, 11.8 DLT1, 1.9, 1.10, 2.3, 3.10, 4.12, 6.2, 7.2, 11.2, 11.5, 17.3 DLT 260, 3.3, 15.6, 16.7 DLT 600, 3.5, 15.6 DLT 2000, 3.5, 3.6, 3.7 15.6, 16.7 DLT 2000XT, 3.7, 7.1, 15.6 DLT 2500, 3.5 DLT 4000, 1.9, 1.10, 2.3, 2.
DLTtape IIIXT, 1.9, 3.7, 4.9, 7.1, 7.2, 7.3, 7.5, 7.6, 16.7 DLTtape IV, 1.9, 2.2, 3.6, 3.7, 3.9, 3.10, 4.8, 4.9, 4.10, 4.12, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 10.6, 11.5, 12.3, 12.4, 15.6, 16.6, 16.7, 17.6, 17.12, 17.13 DLTtape Cleaning Cartridge, 16.3 Dantz, 13.3 Data Acquisition, 1.7, 10.2, 10.3, 10.4, 10.8, 10.9, 11.9 Data Integrity, 1.5, 5.7, 6.7, 8.6, 9.9, 10.7 Data Mining, 1.7, 3.7, 8.4, 10.3, 10.7 Data Recovery, 5.8, 16.3 Data Striping, 9.9 Dell, 4.3, 13.1, 15.3 Desktop Publishing, 3.2, 10.
Electronic Vaulting, 10.11 End of Tape (EOT), 7.5 EEPROM (Electronically Erasable Programmable Read Only Memory), 15.1, 15.2, 15.4, 15.5 Error Correction Code (ECC), 5.7, 5.8, 6.7, 6.8, 11.5 Error Detection Code (EDC), 5.7, 11.5 Exabyte, 11.2, 11.8 F Ferrite Read/Write Head, 3.2 File-by-File Backup, 9.3 Firmware, 3.7, 13.4, 13.6, 13.7, 14.5, 15.1, 15.2, 15.3, 15.4, 15.5, 15.6, 16.5 G GUI, 3.3 Graphic Arts, 1.7, 1.13, 8.4, 10.3 Growth Path, 1.11, 3.9, 11.2, 14.4, 17.3 H Half-Inch DLTtape, 1.3, 3.6, 4.
I IDC, 1.3, 1.4, 1.12, 8.1, 8.2 ISV (Independent Software Vendor), 13.2, 13.3, 13.4, 13.7, 16.6 Image Backup, 9.2, 9.3, 9.10 International Business Machines (IBM), 3.2, 4.3, 13.1, 15.3 Internet, 1.4, 1.7, 3.7, 3.9, 4.2, 8.3, 8.11, 9.1, 10.3, 10.6, 14.1, 16.3 Intranet, 1.7, 3.7, 8.3, 9.1, 10.3, 14.1 J No entries K KPMG, 10.11 L LZ (Lempel Ziv) Compression Algorithm, 6.4, 16.6 Laser Guided Magnetic Recording (LGMR), 11.6, 17.8, 17.9, 17.10, 17.11 Legato, 13.3 Library, 3.8, 5.9, 8.1, 8.2, 8.4, 8.6, 8.7, 8.
M Macintosh, 3.1, 3.3 Magneto-Optical (MO), 11.12 Magneto-Resistive Cluster (MRC) Heads, 2.5, 11.6, 17.9, 17.10, 17.11 Mailbox, 8.10 Mean Time Between Failures (MTBF), 3.8, 4.5, 5.9, 6.1, 6.2, 6.4, 6.5, 8.12, 16.1 Media Cost, 11.2, 12.3, 12.4 Media Durability, 6.5 Medical Imaging, 1.7, 8.4, 10.3, 10.5, 10.8 MeritCare Health System, 10.13 Metal Particle (MP) Media, 4.8 Metrum-Datatape, 10.9 Microsoft, 13.3 MicroVAX II, 3.1, 3.2 Mission Critical, 1.1, 1.6, 3.9, 4.2, 5.1, 10.6, 10.11, 10.14, 12.1, 12.6, 14.
PROM (Programmable Read Only Memory), 15.1 Parallel Channel Architecture (PCA), 2.4, 5.7, 5.8, 11.4, 11.6 Peak Transfer Rate, 6.3 Performance, 1.2, 1.6, 1.10, 1.11, 1.12, 2.1, 3.1, 3.3, 3.4, 3.6, 3.7, 3.8, 4.3, 4.5, 4.6, 5.8, 5.9, 6.1, 6.2, 6.3, 8.1, 8.2, 8.4, 8.8, 8.10, 8.11, 8.13, 9.3, 9.4, 9.7, 9.8, 10.3, 10.8, 11.2, 11.6, 11.8, 12.5, 13.5, 13.6, 13.7, 14.2, 14.4, 17.3, 17.4, 17.7, 17.9, 17.10, 17.11, 17.14 Petabyte, 1.1, 1.2, 4.7 Phase Change Dual (PD) Drive, 11.11 Pivoting Optical Servo (POS), 11.
S SAN, 1.3, 1.4, 1.13, 8.4, SCSI, 1.10, 3.6, 4.4, 5.8, 8.10, 10.16, 10.17, 13.4, 15.2, 15.3, 15.4, 15.5, 16.6 Scalability, 1.10, 4.7, 8.6, 10.8, 14.4, 17.2, 17.4 Scratch Area, 7.5 Seagate, 13.3 Self-Cleaning, 5.6, 5.7, 16.1, 16.5 Serpentine Recording, 2.3, 2.4, 3.4, 11.10 Shelf Life, 5.7, 10.8, 11.11, 16.4 Silicon Graphics, 13.3 Software Compatibility, 13.1, 13.2 Software Support, 13.5 Sony, 1.9, 11.2, 11.8 Specifications, 1.10, 4.4, 5.9, 6.1, 6.2, 6.8, 11.8, 16.1, 17.5 Stacker, 8.3, 8.7 Sun, 4.3, 13.1, 13.
T TF85, 3.4, 3.5 TF857, 3.4 TF86, 3.5 TK50, 3.2 TK70, 3.2, 3.3 Tachometer, 5.2, 5.5, 5.6 Take-Up Reel, 2.2, 2.7, 2.8, 2.9, 2.10, 3.1, 3.2, 5.3, 5.4, 7.3, 11.3 Tape as Disk, 9.1, 9.4, 9.5 Tape Leader Loop, 7.3 Tape Path, 2.6, 2.7, 2.8, 3.4, 3.5, 5.2, 5.3, 5.4, 5.5, 5.7, 6.5, 6.6, 7.3, 11.3, 11.5, 11.7 Tape RAIT, 9.1, 9.8 Tape Stress, 11.3, 11.7 Temperature, 6.1, 6.5, 16.4 3M Company, 11.9, 11.10 Travan, 11.9, 11.10 U UNIX, 4.6, 8.3, 10.14, 10.15, 13.3, 17.6, 17.7 Ultrium, 11.8, 11.9 V VAR, 13.2, 17.
Video-on-Demand (VOD), 1.7, 1.8, 10.3, 10.16, 10.17 Video Distribution, 1.7, 10.3 W White Papers, 16.1 WORM (Write Once, Read Many), 11.11 Windows 3.2, 3.5, 10.13, 10.14, 13.4, 17.7 www.DLTtape.com, 8.11, 13.2, 13.6, 16.1, 16.8 www.quantum.com, 8.11, 13.2, 13.6, 16.1, 16.8 X, Y, Z No entries QUANTUM DLTtape HANDBOOK I.
