There is SATA power line:
In my computer:
the line have two interface which can connect to SATA disk:
In there I have a question:
the line have two branches, one is short and the other is long, I want to know the reason, can the line connect two SATA disks(the power can support two interface power usage)?
or the branch just for distance, if the short can't reach.
The example also in PC power line:
Yes.
Modern computer power supplies almost always put multiple SATA/Molex connectors on a single cable so you can power multiple devices without ending up with awful cable management. While this cannot be extended infinitely, you should not have a problem powering two drives on that "branch".
The computer power cable you showed works the same, though be aware of its rating, usually mentioned somewhere on the cable itself. They're usually meant to power both a desktop and monitor at the same time but generally they should be able to run two computers as well. Just don't exceed the wattage that's listed on the cable.
