Frequently Asked Questions About Quality

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

Do we really need flawless discs? It is not practical to meet demands for perfect quality.

Complex requirments of ISO and other standards can be overwhelming. Users are confused when discs that violate one or more criteria still work.

The stated purpose of standards is to achieve information interchange between different systems. Discs conforming to the standards will be readable in all good drives. Achievement of this noble goal is difficult because standards exist only for the discs, not for drives.

Failure of a good disc indicates that the drive or user handling is faulty. Conversely, defective discs that are readable in some drives are at fault when the inevitable read failure occurs. Interchange failure is a probability, not an absolute results. Bad discs may be unreadable 0.1%-100% of the time while good discs fail infrequently.

Full testing to every requirement of the standards is nearly impossible, requiring expensive equipment and lengthy test times. Even then, full testing of a few samples does not provide 100% confidence in untested discs from the same lot. A practical approach is to design a sampling plan that routinely tests for major defects, perhaps using outside resources for more comprehensive testing. Try to achieve nominal test results, not just a pass indicator, to obtain a high confidence level in the entire lot.

But what should be the response to non-ideal test results? If values are only marginal, then continue production but implement corrective actions that will result in a nominal process. If resuts are outside of specification limits, then a decision must be made based upon the test data. Defects that clearly impair functionality indicate that product manufacture must be halted until the problem is fixed. Often the decision is not that clear.

For example, a rush job arrives from a customer for duplication or replication, and incoming inspection of the gold master to ISO 9660 reveals logical defects. Should the manufacturer refuse the gold master and anger the client? Should the manufacturer proceed and deliberately ship defective discs? Neither is acceptable because the manufacturer should not be burdened with this decision. Contact the client instead, provide details of the defect, and request either a waiver to proceed or await a replacement gold master. Follow up with support that facilitates corrective action by the client, avoids future difficulties of this nature, and strengthens your reputation for service as well as quality