根據 "廠商在網頁上提供的資料"，RAM 的保存年限還比 R 遜。

不重複貼文了，請參考之前的討論串：
http://forum.pcdvd.com.tw/showthrea...#post1077574401



染料怕變質 (R)，但相變材料也會怕改變結晶的狀態，請參考下文：

4. How Long Can You Store CDs and DVDs and Use Them Again?
http://www.clir.org/pubs/reports/pub121/sec4.html

(節錄部分文章)
4.3 CD-RW, DVD-RW, DVD+RW, DVD-RAM Discs
RW and RAM discs are generally not considered for long-term or archival use, and life expectancy tests are seldom done for this medium. Rewritable discs use a phase-changing metal alloy film for recording data and aluminum for the reflective layer. The alloy film is not as stable as the dye used in R discs because the material normally degrades at a faster rate... (該金屬層不如染料穩定，因為材料品質降低的速度較快)

The phase-changing film is affected primarily by heat, but ultraviolet (UV) light may also be a factor in the aging process. (相變材質主要會被"熱"影響，但 "紫外光"也會) The combination of high temperature and UV light may further accelerate the aging process. (高溫 + 紫外光會加速老化過程) The combination of high temperatures and high relative humidity will also most likely accelerate the aging process, just as it does with the organic dye used in R discs. (和 R 一樣，高溫 + 高濕度也會加速老化)...

The data on the phase-changing metal alloy film layer can be erased and rewritten to a limited number of times (about 1,000 times for RW discs and about 100,000 times for RAM discs). This rewriting does, however, affect disc life expectancy; RW or RAM discs archived after the first recording should have a longer life expectancy than those that have undergone several erase-recording cycles. (覆寫會影響預期的壽命，寫一次比重複寫入幾次後的預期壽命高) Given the normal degradation rate alone, the life expectancy for RW and RAM discs will be less than that of R discs. (依照正常的速度，RW 與 RAM 的預期壽命較 R 低) Add to that multiple rewrites, and the life expectancy can be even less. (重複寫入後，預期壽命更低)


重要資料，不要僅依賴單片儲存媒介。