為什麼CD和DVD從中心向外新增資料？

在家裡燒錄CD或DVD時，您可能會感到奇怪，為什麼資料總是從中心向外新增？如果資料被反方向新增，就像舊的乙烯基記錄被修復一樣，這真的有關係嗎？還有別的嗎？今天的超級使用者問答帖子回答了一位好奇的讀者的問題。...

在家裡燒錄CD或DVD時，您可能會感到奇怪，為什麼資料總是從中心向外新增？如果資料被反方向新增，就像舊的乙烯基記錄被修復一樣，這真的有關係嗎？還有別的嗎？今天的超級使用者問答帖子回答了一位好奇的讀者的問題。

今天的問答環節是由SuperUser提供的，SuperUser是Stack Exchange的一個分支，是一個由社群驅動的問答網站分組。

問題

超級使用者讀者Burgi想知道為什麼CD和DVD會從中心向外新增資料：

Recently, I had to burn a DVD for the first time in ages and I was wondering why CDs and DVDs start adding data in the center of the disc and work their way toward the outer edge.

Older rotating-disc media like vinyl records started from the outer edge and went in toward the center, so it could not have been for historical reas***.

I am looking for good sources that explain the reasoning for this data structure/setup.

為什麼CD和DVD從中心向外新增資料？

答案

超級使用者貢獻者DavidPostill為我們提供了答案：

Why do CDs and DVDs add data from the center outwards?

Note that the assumption made in the question above is incorrect.

Summary

For historical reas***, writing (and reading) from the inside makes sense (different sized discs are possible as explained in other answers).
For read performance reas***, modern discs may be written (and read) outside in or even in both directi*** (dual layer).

Notes

Most discs are a standard size.
Commercially produced CDs and DVDs are not written at all, they are stamped on a press.

Source: The Difference Between Commercial and Home-Recorded DVDs

The rest of this answer concentrates on the performance aspect. The excepti*** to writing (and reading) from the inside are Xbox games (and other game c***oles’ games) and Dual Layer DVDs (movies).

Xbox Games

Xbox games have the data written from the outside in for performance reas***. Since the outside is spinning faster than the inside, the data can be read faster.

Source: Hardware Behind the C***oles – Part I: Microsoft’s Xbox

Dual Layer DVDs (Movies)

Dual Layer DVDs can be written in either direction, there are two write modes. Most movies are written using the opposite track path technique. A movie will be split across across the layers, so no seek back to the inner edge is needed at the layer change point.