Are “stamped” discs really so perfect?
“Stamped” discs (or, if you want, “aluminum”) can be made in various ways. The most common is, to be precise, injection molding, rather than stamping. Modern technologies make it possible to achieve extremely high manufacturing accuracy, however, compact discs made in this way will be prohibitively expensive. Therefore, really “stamped” discs contain many single, at least errors. The main thing is that the available number of errors does not cause a decrease in read speed.“Branded” discs really read the same way without the slightest problem on any CD-ROM. The read speed of “branded” disks in tests played the role of calibration data, since they can be used to obtain real drive characteristics in the absence of errors.
As for the most common “pirated” discs in our country, everything is not going smoothly here. If initially the technology admits a certain number of errors, then the slightest violation of the technology (increased dustiness of production facilities, production of a large number of copies from one matrix) will lead to a poor readability of the disc. To the credit of our pirates, I should note that in most cases the “aluminum” “pirate” discs are made with very high quality. However, out of a random selection of 25 discs, 3 discs of poor quality were detected.
A sharp decrease in the reading speed in certain areas of the disk surface indicates an unacceptable number of errors in these areas. All these discs are confidently backed up. However, it can be seen that the disc “3 Heroes” at the end is poorly recorded. It is enough to have a little dirt or minor scratches in this area so that it stops reading.