Bulletin: 004 December 1996

Since producing a Compact Disc is very complex, quality control measures are taken throughout the entire manufacturing process. This ensures that the final product will meet the customer's exacting requirements.

Media Check-in

When input media is received, a check-in step is performed to verify that the media contains the data the customer intended for mastering. The paperwork accompanying the media should indicate the total number of bytes or records on the media, as well as the Volume ID of the data set if applicable. This information is then compared to the input media for verification. If the given information differs from what is found on the input media, the customer will be contacted for resolution of the discrepancy. If this information is not supplied by the customer, this verification step can not be completed.

Data Preparation

For jobs that require data preparation, the customer data is restored from the supplied input media and formatted for use in mastering. File and byte counts are verified and the formatted data is compared back to the original data to ensure data integrity. A virus scan is also done at this time to ensure that the data is free of any known viruses.

Mastering

The mastering step is where the formatted data is transferred from the input media to the glass master. During the data transfer the layered error correction and detection codes (LECC and EDC) are regenerated and the EDC is monitored in each block to ensure that the data is transferred correctly during the master recording process.

Glass Master Inspection

Following the master development and further processing, the glass master plate is tested for both electrical and mechanical characteristics, including C1 and C2 Block Level Error Rates (BLER). These test results must fall within Statistical Process Control (SPC) limits. This ensures that all parameters are within specification prior to disc replication.

Replica Inspection

Immediately after production, the active data area of each CD replica is 100% laser scanned for defects that would affect readability. Also, sample discs are tested for electrical and mechanical characteristics to ensure that all disc parameters, including BLER, remain within the SPC limits. As described, this process is very thorough and Imation's low BLER rates result in a wider correction margin for end user introduced errors such as scratches, smudges, etc.

Data Verification

This process is for final verification of complete data integrity. A replica from every master made is compared, byte for byte, to the original data input media using a standard CD-ROM reader. This step ensures that no changes were made to the original customer data at any point during the mastering process.

General Information

Please contact Imation Technical and Customer Service at: 1-800-336-3636 or at 1-715-235-5567.

Copyright 1996 Imation. All rights reserved.