Frequently Asked Questions About Flexible Disks

Please contact Media Sciences if your questions are not answered on these pages.

I agree with your comments about high clip diskettes, but many say that high clip is essential to long term, archival storage quality. Does clip level deteriorate with time?

It is truly amazing how every diskette quality issue must be related to clip level, one of the least important quality indicators. I do not know of any relationship between clip level and archival quality. Clip levels should not change with time. There are certain effects that can change clip level, but selecting high clip diskettes does not isolate and remove these effects.

Liner materials can deteriorate with time. Either liner fibers or the bonding agents can chemically interact with binders and other components of the magnetic coating. This chemical reaction roughens the surface of the coating. The result is lower clip levels, lower 2F TAA, higher overwrite, higher peak shift, and higher torque. The initial clip level cannot predict this deterioration. Accelerated aging at temperature and humidity extremes is normally used by the diskette manufacturer to control this quality issue.

Internal stresses are present in media. Improper processing can generate poor substrate or hubbing quality and warped media. Special substrate treatments are required both before coating and after the cookie is punched. Some coaters eliminate these steps in response to cost pressures. The punched cookies look like potato chips! Off-center hubbing or center hole-hub misfits also can cause deformation of the cookie. Although disk warping can be relieved over time, it can also worsen. Initial clip level is not relevant. Only careful visual inspection and modulation tests can identify such problems in advance.

Jacket quality is very important to 5.25" and to 8" archiving, since built-in strains cause jackets to curl after years of storage. Jacket warpage is often so severe that the disk cannot be rotated. If you have important information on such diskettes, copy it to 3.5" before it is too late. The bad news is that even 3.5" disks can have shell problems. Very stable ABS material was originally used to manufacture rugged shells with ample wall thickness. Cost pressures have resulted in reduced wall thickness. Less expensive substitutes are being used for ABS, and some give excellent performance. Other substitutes can warp, especially during transportation or storage at elevated temperature and humidity conditions. Clip level is irrelevant. Only special tests and assurances from the manufacturer can indicate archival quality.

Lifter tabs are an important component of 3.5" diskettes. Tabs of the proper thickness using dimensionally stable plastics will maintain proper torque and cleaning action for many years. Pricing pressures can result in thin lifter tabs or the use of less expensive, dimensionally unstable materials. Clip level is not closely related to lifter tab quality. Again, special tests and representations by the manufacturer are the answer.

Our society seem to demand short, easy answers. Thoughtful discourse is replaced by four word bumper stickers. Fifteen second TV sound bytes are substituted for intelligent discussion. Clip level is just a symptom of a deeper affliction. Avoid this disease. Shortcuts are the problem, not the solution. Many resources are available that will assist you to attain both higher quality and lower cost. Use them effectively.