Storage Must Prepare For The Zettabyte Universe

Remember when bubble memory was the top storage technology? Then along came the faster, cheaper, and higherdensity hard-disk drive (HDD).

Of course, bubble memory replaced core memory. One example of the latter was the Apollo Guidance Computer, which incorporated the read-only core rope memory (it resembled a rope of woven copper wire). The Apollo 11 lunar mission in July 1969 used 36 kwords of core rope memory ROM with a cycle time of 11.7 µs to store a program that, when printed, required six inches of 11- by 15-in. fan-fold paper.1 But enough about the past. What about the future of storage?

STORAGE VISIONS
During January’s Storage Visions Conference in Las Vegas, Tom Coughlin of Coughlin Associates said that we can expect increases in HD/SD television streams and downloads, plus a continued increase in music downloads. He expects the average household in the U.S. to require more than a terabyte of storage space for home entertainment by next year, approaching 5 Tbytes by 2013. Add in personal data and home backup requirements, and these figures jump to more than 2 Tbytes by next year and nearly 9 Tbytes by 2013.

These trends will drive the sales of HDDs in consumer electronics from just under 100 million in 2008 to 250 million in 2013, mostly in set-top boxes, external storage, auto entertainment, and personal media players (PMPs). Flash memory will reap similar rewards, with most flash for consumer devices going into cell phones, and the rest divided among MP3 players, PMPs, and digital cameras. Flash will appear in more than 1.5 billion devices this year and approach 2.5 billion in 2013.

Optical drives buck the trend, though. Their use in auto navigation and entertainment, camcorders, and DVD players will peak in 2009 at around 300 million units and then decline to less than 250 million units by 2013.

“The digital universe will grow six-fold, from 161 exabytes in 2006 to 988 exabytes in 2010,” says John Rydning of IDC, describing the total amount of data in the world. An exabyte is 2⁶⁰ bytes, or 1 quintillion bytes or 1 billion gigabytes. After exabytes come zettabytes (2⁷⁰ bytes), yottabytes (2^80M bytes), xonabytes (2⁹⁰ bytes), wekabytes (2¹⁰⁰ bytes), and vundabytes (2¹¹⁰ bytes). This continues through lumabytes, or 2²¹⁰ bytes. No names have been locked down beyond lumabytes.

So where is all of this data going, and what’s driving it? According to Jim Handy of Objective Analysis, “Mobile applications will migrate to flash memory [while] static applications will favor [magnetic] HDDs.” In the 1980s, the driving factor was text files, followed by photos in the 1990s, and music in the 2000s. Trends are moving to video now. Going forward, Handy’s company believes library replica and Internet replica will drive data storage. After that is anyone’s guess.

If we look at enterprise storage in particular, IDC noted a few trends in the January 2008 issue of InfoStor Magazine. First, the use of parallel SCSI is rapidly declining from almost 50% in 2006 to under 10% in 2009, while the use of Fibre Channel will stay about even over the same time at around 20%. Serial Attached SCSI will grow from under 10% usage in 2006 to just over 25% in 2009, while Enterprise SATA will grow from just over 20% to just under 50% in the same period.

Speaking of enterprise storage, Hubbert Smith of Samsung noted some data-center application requirements during a recent Storage Power Lunch event. The parameters used included power, capacity, reliability, performance, and vibration tolerance across a multitude of applications, including surveillance, embedded, and scientific (see “Application Requirements,” www.electronicdesign.com, ED Online 18634).

WHAT’S NEW & EXCITING
With all of the fascination surrounding more glamorous technologies, storage is sometimes seen as rather dull. Yet since virtually every electronic design has some form of storage, its importance can’t be overlooked. And despite what some may think, storage isn’t always boring (see “DDR3's Impact On Signal Integrity,” ED Online 18633).

MetaRAM’s recent MetaSDRAM chip set increases the capacity of a DRAM-based, dual-inline memory module (DIMM) by a factor of four. It’s also significantly cheaper and requires less power than technologies that use other methods to attain the same capacity on a DIMM (see “SDRAM Chip Set Boldly Goes Where No Man Has Gone Before,” p. 23).

The Violin Switched Memory (VXM) from Violin Memory provides a huge amount of DRAM- or flash-based storage. It employs a unique patent-pending switched-memory architecture (versus traditional bus topology) that delivers an impressive 1.7-Gbyte/s bandwidth.

This new architecture allows for incredible scale, since a singlememory controller supports more than 4000 memory devices with a latency less than or equal to that of a repeated bus network, saving more than 75% in power (Fig. 1). It also provides fault tolerance, whereby a module can experience failure without data loss or application interruption.

The DRAM and/or flash memory are configured into Violin Intelligent Memory Modules (VIMMs). Each VIMM can be a 6-Gbyte DRAM or 64-Gbyte NAND flash. The company packs up to 84 of the VIMM modules in a standard 2U-height (88.9 mm) form factor in a product called the Violin 1010 (Fig. 2). An entire rack full of Violin 1010 products would provide a 100-Tbyte RAM disk.

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