Hi, I have added a second HDD to my 9880. It's a fairly easy task. If I am remembering correctly, you do need to set the jumpers on the 2nd HDD to slave. I believe I tried the CS jumper and using no jumper, and the system could not see the 2nd drive.
You will need some hard drive screws so that you can mount the 2nd drive in the caddy. The caddy that came with your system should be a double decker, so nothing more to buy.
Disconnect the power, remove the battery, press the ON button so that the system discharges any charge remaining. Either use a grounding strap, or remember to keep touching a metal part of the case before you touch any of the internal components of the system.
Remove the HDD cover then remove the screws for the caddy. Using the clear plastic loop, gently pull up to disconnect the ribbon connector from the MB.
It is easier to connect the new HDD to the ribbon cable if you disconnect the ribbon from the already installed HDD. You can wiggle the additional drive and connect it to the ribbon without removing it, just be careful.
Put the HDD you want to be the main HDD in the slot where the HDD is already mounted. (If you are simply adding a bare drive, then put it in the open slot.)
Once you secure the additional drive and reconnect the ribbon cable, gently lay the assembly back in the system. The hardest part for me was getting my fat fingers in between the case and the caddy to reconnect the ribbon cable to the MB. One you do that, then secure the caddy using the screws you removed from it earlier.
If you are comfortable, before you replace the HDD cover, you can reconnect the power and make sure the system boots up and recognizes the 2nd HDD. If it does NOT power up correctly, disconnect the power, press the ON button, etc.....
Then remove the ribbon cable connector from the MB and reconnect it. With my fat fingers, it took a little work to get the connector lined up correctly. Do NOT force the connector into the slot. It should connect with about as much pressure as it takes to put the cap back on a plastic film cannister.
Once you reconnect the power and verify that it runs, flip the system over and reinstall the HDD cover. If it still does not recognize the additonal HDD, go through all the safety stuff and then remove the entire caddy. Make sure the ribbon connectors are securely fastened and make sure you used the correct jumper settings.
There are some OK pictures in the user manual on removing the HDD caddy, etc. Look at them before you start.
It really is an easy task, I just tend to write instructions that my mother can follow.