MSI 694D PRO Manual page 19

IDE1(Primary IDE Connector)
The first hard drive should always be connected to IDE1. IDE1 can connect
a Master and a Slave drive. You must configure second hard drive to Slave
mode by setting the jumper accordingly.
IDE2(Secondary IDE Connector)
IDE2 can also connect a Master and a Slave drive.
IDE3 (Third IDE Connector)
ATA100(1) can also connect a Master and a Slave drive.
IDE4 (Fourth IDE Connector)
ATA100(2) can also connect a Master and a Slave drive.
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