AN INDUSTRY PERSPECTIVE – Terry O’Kelly
The Happy Medium

Terry O’Kelly is a veteran in data storage with over 30 years experience manufacturing and marketing magnetic tape, optical discs, flash memory, and hard drives for such companies as BASF, Kodak, Memorex, and Imation.

Three principal criteria for information storage media have always been:

1. durability—the ability to last long enough to get the message across and leave a record for some time to come;
2. accessibility—the right size, weight, and format to make the records available to those who may need them; and
3. capacity—the ability to store large amounts of information in a medium that does not violate accessibility.

“Cutting edge” technology indicates that some blood may be shed in the contest between durability and capacity. The latest introductions in storage media create excitement because of their impressive advances in capacity.”

The trick in manufacturing storage media is to balance all three criteria in ways that satisfy users. Sumerian clay tablets have survived 5,000 years; but they are heavy and limited in information capacity. Storage technology has seen amazing advances resulting from the concentration on increasing storage capacity, particularly over the last quarter century; but legal requirements such as Sarbanes-Oxley have lately placed more weight on the issue of durability. And this newly sought after durability is typically in direct conflict with capacity.

Today’s storage media are most often magnetic, optical, or a combination of both. Magnetic media are written and read by either direct physical contact (tape) or a very slight physical separation between the medium and the reading device (hard drives). Optical media rely on light waves instead of physical contact. Improvements in the capacity of magnetic tapes have been based on moves from simple and stable ferric oxides to more advanced and less stable particles and the development of ever-smaller data tracks. Optical discs, too, have seen similar advances, transitioning from the reasonably stable dyes used in CD-Rs to less stable dyes that react to smaller wavelengths of laser light. Today’s Blu-ray disc, like a hard drive platter, has to have its optical pickup head extremely close to the disc in order to resolve the miniscule data pits and tracks that provide 25GB per layer.

There are claims and counter-claims about the reliability of different storage media. A tape proponent recently claimed that even the best CD-Rs would last only five years. We do know that analog audio tapes from 1935 still play and sound better today than they did then due to better heads and electronics, but their cellulose acetate backing makes them as fragile as the Dead Sea scrolls. Analog audio masters from the 1950’s sound superb today, and they are far more durable. As for the CD-Rs, 13-year-old recordings I have tested show results identical to the best of the latest 52X discs. Strict environmental tests based on double-stress points of heat and humidity have indicated that they may last over 100 years if well cared-for. DVD+/-R media under the same conditions indicate a life of 40 years or more. As for the most recent high-capacity, high-definition discs, these same test conditions suggest that today’s early samples are best suited for grocery lists and not for anything expected to last longer than that.

“Cutting edge” technology indicates that some blood may be shed in the contest between durability and capacity. The latest introductions in storage media create excitement because of their impressive advances in capacity, seldom because of their improved durability. In time, developers must and will address stability and reliability and make the improvements needed to balance both durability and capacity. So for the present at least, The Happy Medium may not be the latest, greatest format, but the older tried and true variety.