請教一個問題，普通的硬盤可以允許幾個主分區,拓展分區。。

我的電腦隻有一塊硬盤，沒法再加了。 裝了雙係統後 winxp, linux，發現用繼續分割硬盤(partition magic)有困難。 現在考慮重裝一次，不過需要先計劃好如何分區：
my current partition table looks like this:
windowsXP: 2 primary partitions.
linux : 1 primary(/boot), 1 extended partition.

since I need to have 3 partitions for windows, the current scheme is no good. i was wondering if it is possible to create 2 primary partitions and 2 extended partitions on my hard disk, like this:
winXp: 1 primary,
1 extended:
-logical partition, for backup
-logical partition,for filesharing with Linux

linux: 1 primary(/boot), 1 extended partition(/root, /home).

Any help? Thanks very much..