If a record start position of the user data is learned beforehand in the next recording layer, the guard block is formed on the next recording layer prior to the recording of the user data.

如果下一个记录层的用户数据的记录开始位置预先知道，在用户数据记录之前，在下一个记录层上形成保护块。

youdao

Taking place, done, or given beforehand; prior.

目前的危机比以前发生过的都严重。

youdao

That is unless some prior arrangement about sharing profits was made privately beforehand with the client.

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