Keeping the enterprise afloat: the drive to terabyte-class tape cartridges.

Imagine yourself in a boat on the ocean. A windy day whips up the waves and the boat takes on water. Physics says that when the weight of the boat becomes greater than that of the water it displaces, it will sink. That is the feeling of many IT managers in the trenches today: rising data volumes are threatening to swamp storage resources. If the industry stands still, IT will spend more time bailing, and less time advancing their businesses.

Rising data volumes are the core reason behind the drive to dramatically increase tape cartridge capacities into the terabyte-plus range. We've heard the statistics. Enterprises store four times the data they produce as backups and archives. Increasingly strict industry regulations are enforcing longer and more effective data retention requirements. Personal health data must be increasingly transportable, accessible and secure, due to customer demand and HIPAA requirements, raising the need for secure data protection and archiving. The implementation of Sarbanes-Oxley has caused increased retention of corporate financial information. Industries like broadcast and entertainment are facing massive backup and archiving requirements as they aggressively convert to digital processes.

In addition, massive data volume growth is increasing the importance of near-line and off-line storage for disaster recovery and business continuance. On-line data storage is more than ever seen as one element in a multi-platform storage architecture, recognizing the growing importance of near-line and off-line storage. Because it is portable and removable, tape is critical to an effective disaster recovery plan, playing a complementary role to on-line replication strategies. With the threats of sabotage, viruses and malicious data corruption, and natural and unnatural disasters hanging over every organization, the need for an off-site/off-line data copy that can be restored at any time, anywhere is critical to successful business continuance strategies.

Magnetic tape has been the dominant technology used in the last 50 years to archive and store digital data. This technology offers significant advantages over competing technologies, and current trends indicate that this will continue to be the case in the foreseeable future. Tape media continues to be the most efficient way to backup and archive massive amounts of data on a TCO basis. But for tape to continue to be relevant over the long term, the industry must invest in new, evolutionary tape technologies that improve capacity, speed and reliability. To keep the enterprise afloat, the storage industry must deliver more than just a bucket--we must deliver a bigger and sturdier boat.

The Tale of the Tape Cartridge (and the technology behind it)

Tape media and cartridges have changed dramatically over the years, as improvements continue to be made across virtually every physical parameter of tape from the thickness of substrate and magnetic layers, size and density of magnetic particles, track width and number of data tracks, to the length and speed of the tape within a cartridge. This broad improvement delivers continually increasing capacity on a single tape cartridge.

Each cartridge is a critical component of the mass storage system. Over a one-year period, the data spends over 8,000 hours in the tape cartridge. The drive must write and read that data accurately, but the media must safely store and protect that data over a long period of time and over many recurring lifecycles.

Advanced technologies such as servo writing (which enables precise data reading/writing) become even more important as capacities increase. Tape backcoating formulations will continue to have features such as texture, compressibility, and static reduction required to reduce wound-in debris and tape layer slippage and to protect servo and data tracks.

With increasing demand for digital data to be archived, there is a great need to keep increasing capacity and transfer rate for data cartridges. This is accomplished with increasing bit and track densities on a given tape, and increasing the amount of tape in a given cartridge.

To enable increased bit and track densities, media manufacturers, including Imation, have used increasing coercivity and smaller size metal particulate (MP) pigment particles for every successive generation of tape products. With continuous advancements in MP technology development, we believe MP technology will be the most competitive technology for removable magnetic tape media in the foreseeable future--delivering 1TB-capable native capacity cartridges within the decade.

Along with using more sophisticated MP pigments and the related formulation chemistry, the media processes used to enable the media to be produced play a significant role in the end properties of the media. The higher bit and track densities needed for future products necessitate media with high signal to noise ratio (SNR). This is accomplished through a thin magnetic layer on top of a nonmagnetic layer, or sub-layer, coated on a thin flexible plastic substrate with a conductive backside coating.

In order to develop magnetic media suitable for tape products, several steps are taken to ensure high-quality magnetic tape. The process begins by creating dispersions of magnetic, non-magnetic and backside chemistries. To create these fine dispersions, the appropriate pigments, binders and other additives impinged are milled together. These dispersions are coated using thin film coating techniques on a high-speed moving web, and dried in high-temperature, low air turbulence ovens. During the drying process, the magnetic particles are aligned in the direction of the moving substrate to further enhance the electromagnetic properties of the media, improving its signal output. The magnetic media then is calendered in a stack of rollers to improve the packing of the magnetic pigment and smoothness of the media, again giving a boost in the electromagnetic performance of the media. After calendering, the media is slit into the desired tape width. This media is then servo-written and wound into cartridges.

Tera Angstrom Technology

Imation is addressing the challenge of building terabyte-class tape with its new Tera Angstrom Technology, a proprietary metal particulate advanced formulation and manufacturing process to develop magnetic media that leads to uniform surface smoothness and higher SNR, and therefore enables the higher capacity and transfer rates required for future tape storage products. Imation's Tera Angstrom Technology is based on three proprietary elements:

Impingement Process using high-pressure impingement technology to achieve nanometer size particles. In preparing the magnetic and non-magnetic dispersion, high-pressure impingement jets use >10,000 psi to force magnetic particles against each other blasting apart the magnetic clusters to separate them into nano-sized elements. Large size particles, as seen in conventional homogenization, are virtually eliminated by using this proprietary process. Particle size and uniform distribution leads to overall magnetic layer uniformity.

Quiescent drying process with low air velocity and magnetic coil orientation. To enable precise particle orientation during the drying stage, Imation's proprietary quiescent drying process creates a delicate environment using low air velocity and magnetic coils for precise particle orientation. This process eliminates coating disturbances and orients the particles precisely to allow for maximum bit density and storage capacity.

In-line Calendering Process to achieve surface smoothness on the order of Angstroms. The in-line calendering process incorporates a stack of rollers with an ultra-smooth finish to compress the tape achieving surface smoothness on the order of Angstroms.

In each of these three areas, Imation's techniques provide a significant improvement in performance over conventional approaches. The three key process components outlined above are critical steps in producing a uniform coating layer with a strong signal strength (high SNR--signal to noise ratio). A strong SNR leads to reduced errors, increased productivity and increased throughput. Similar to the static on television, a weak SNR can equate to noise or "static" distorting the read accuracy. Just as you may strain your eyes to view a static-filled program, the drive head strains to accurately read and write data if there is a weak SNR. This slows processing time or results in an error, which affects overall throughput. High SNR levels are achieved through media surface uniformity to minimize noise and amplitude fluctuations as the head travels the length of the tape. Magnetic clusters can also produce noise; therefore, Imation's impingement process ensures a homogenous formulation with smaller particle sizes properly oriented through quiescent drying and tightly compressed in-line utilizing Imation's proprietary calendering process.

Imation (at that time, 3M's Data Storage Division) was the first company to offer magnetic tape products for IBM tape drive systems more than a half-century ago, and continues to invest in magnetic technology development today. In May, Imation began operation of its new advanced magnetic media coating facility in Weatherford, Oklahoma. Incorporating Tera Angstrom technology in a real production environment, the facility is the result of a $50 million investment by Imation in technology designed to manufacture terabyte-class media in high volumes leading to a faster time-to-market.

Imation's proprietary Tera Angstrom Technology will be the cornerstone for the development of future magnetic media products that reach terabyte capacities and beyond, which will help keep the boat afloat and carry the enterprise a long way into the future.

www.imation.com

By Dr. Subodh Kulkarni

Dr. Subodh Kulkarni is director of Imation R & D at Imation's worldwide headquarters (Oakdale, MN)