Recording error cannot record on this disc

However, with regard to the use of recordable CD, archival experience and testing has led to a recommendation in maximum error levels that is approximately 25% of the red book recommendations. The DVD specification also states that any eight consecutive ECC blocks (PI Sum8) may have a maximum of 280 PI errors and jitter should not exceed 9%. Other types of error measurement are defined, but at the time of writing no agreed threshold for archival purposes has been developed. Industry standards state that the POE should be zero.

The two main DVD error measurements are Parity Inner Errors (PIE) and Parity Outer Errors (POE). Though measured differently, the actual jitter measurement is largely equivalent in the two disc types, the main error measurements, however, are quite different. Jitter in DVDs is customarily measured in percentages. Table 1 Section 8.1, Maximum error levels in an archival CD-RДЁ.1.9.5 The construction of a DVD is significantly different to that of the CD, and though there are many aspects in common the criteria that applies to CDs does not necessarily apply to the DVD. The 3T jitter values should not exceed 35 nS (Fontaine and Poitevineau, 2005). Jitter is also a useful diagnostic indicator of the quality of the data recorded on a CD and should be measured after writing. A BLER average of 1 and a peak level of less than 20 are easily achievable. In practice error levels much lower than this are achievable and preferable, and must be met in order for the disc to have any archival life before recopying becomes necessary. These are maximum levels after which CD-Rs must be copied. It is necessary to measure other test parameters, among them E22, E32 (uncorrectable errors), and frame burst errors (FBE, sometimes called Burst Error Length or BERL), which are valid end-of-life indicators.When these parameters exceed the limits specified below, it indicates a need for immediate duplication, assuming the disc containing archival information is still readable.ДЁ.1.9.4 Errors in archival CD-Rs should not exceed that specified in the table below. For data purposes this lower level is vital.ДЁ.1.9.3 Studies have shown that BLER alone is not a very useful measure when determining LE, because defective discs may exhibit BLER well under 220, or indeed under 50. The standard for recording general data on CD, otherwise known as Yellow Book standard, specify a BLER of 50. Standards ISO/IEC 10149 and ANSI/NAPM IT9.21-1996, or Red Book standard, specify a maximum BLER rate of 220. BLER is the number of erroneous blocks per second measured at the input of the C1 decoder (see ISO/IEC 60908) during playback at the standard (x 1) data rate averaged over a 10 second measuring period. Alternately, some standards and suppliers specify an acceptable Block Error Rate (BLER). The ANSI/NAPM IT9.21-1996 вЂ“ Life Expectancy of Compact Discs (CD-ROM)- Method for Estimating Based on Effects of Temperature and Relative Humidity, discusses many of these issues. To most end users, a CD-R or DVD-R/+R reaches the end of its life when the drive no longer reproduces the data written on the disc, but because drives are not governed by standards, a CD/DVD that will not play on one drive may well play on another. In the well-documented digital archive, metadata will record the history of all objects, including a record of error measurements and any significant corrections.ДЁ.1.9.2 Life expectancy of CD-R or recordable DVD is a many varied topic. On the other hand, a comprehensive testing regime allows for best possible planning of preservation strategies by acting on the known, objective and measurable parameters that digital archiving make possible. The error correction capability of most replay equipment will mask the effects of degradation until the errors are well into the uncorrectable region.When this point is reached, all subsequent copies are irreversibly flawed. This cannot be stated too strongly no collection using CD-R or DVD-R/+R as an archival carrier should be without a reliable tester.

8.1.9.1 The only way to know the condition of a digital collection is constant and comprehensive testing.

Recording error cannot record on this disc