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Last
Revised: 8/1/05 Deprecated: 7/1/2009, remains for archival purposes
Applies to:
- CDR vs CDRW
- DVD+R vs DVD+RW
- DVD-R vs DVD-RW
PROS AND CONS
OF R
BETTER
COMPATIBILITY & RELIABILITY
Disc WRITE success rate is around 98%, vs 90% with RW. You stand a
fairly high chance of a certain brand of RW not usable with your
particular drive. After successful "burn" of the disc, READ success rate
at various drives is around 99% for R and 95% for RW. Long-term
readability deteriates at lower rates for R.
HIGHER
WRITE SPEED
Most drives will write to R faster than to RW. No difference in Read
speed. There's also the time spent in erasing, but it's not an attended
process. Start it and let it complete.
ONE-TIME, NON-REUSABLE
R COST is much higher than RW for frequent use.
See http://bravotech.us/info/stomediacost.htm for my cost analysis. For
a typical scenario of backup scheme with 10x daily + 10x weekly
rotation, the total media cost is $63 for RW, vs $315 for R. Figures
based on 3-year period factoring in a 40% failure/replacement rate for
DVD+RW and 5% spoilage/failure rate for DVD+R.
SUMMARY
- R is simpler.
- R is slightly more reliable.
- RW has low tolerance on specific drive and media compatibility
- RW is much cheaper and earth-friendly.
- RW is more complex: Must keep track of recycle schedule and
perform erase.
RECOMMENDATIONS
For routine & frequent
daily/weekly backups, RW media should be used. Occasionally, that should
be supplemented by R media. Typical scenarios:
- Archival (permanent) backups.
- Infrequent Monthly/Quarterly/Annual backups or Off-site copy.
- Just before high risk operations, such as upgrade, etc.
- Ad hoc data transfer (for clients/vendors/branch offices).
- Creating experimental disc, requiring numerous revisions.
See Also:
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