Which type of power connector should be used to connect to a PATA hard drive?

The white one that fits. :)

Here's <a class="url" target="_blank" rel="nofollow noreferrer" href="/to/?target=http://www.nuggetlab.com/comptia_files/equipmentperif_Molex%20style%20power%20connector.jpg">a picture for you</a>

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They're not always white, sometime black.