Dell Precision 490 - Manual (Page 52)

General Drive Installation Guidelines
When you install a drive, you connect two cables—a DC power cable from the power supply and a data cable—to the back of the drive. The other end of the
data cable will connect to either an expansion card or to the system board. Most connectors are keyed for correct insertion; that is, a notch or a missing pin on
one connector matches a tab or a filled-in hole on the other connector.
Power Cable Connectors
When connecting an IDE data cable, align the tab on one connector with the notch on the other. When disconnecting an IDE data cable, grasp the colored
pull-tab and pull until the connector detaches.
When you connect two IDE devices to a single IDE data cable and configure the devices for the cable select setting, the device attached to the last connector
on the data cable is primary or the boot device, and the device attached to the middle connector on the data cable is the secondary device. See the drive
documentation in your upgrade kit for information on configuring devices for the cable select setting.
When connecting a SAS or SATA cable, hold the cable by the connector at each end and press firmly into the connector. When disconnecting a SAS or SATA
cable, hold the cable by the connector at each end and pull until the connector detaches.
SATA Data Cable Connectors
SAS Data Cable Connectors
NOTICE: If metal shields are present in your computer configuration, they must be installed at all times while your computer is in use or your computer
may not function properly.
1 power cable
2 power input connector
1 SATA data cable
2 SATA data connector (on the system board)
3 SATA drive
1 power cable
2 SAS data cable
3 SAS connector
4 SAS drive