While I worked on similar other brands a few years ago, it's usually not supported to swap a drive like that.
At 16 channels I'd think about reducing the channel count or frame rate since most incidents are caught at a lowly 1 frame per second.
Also, if you are getting more than a day on that drive, you again have more than enough time to get your evidence video out.
With that out of the way, even when I worked on these, very few would use more than one drive. Very few.
Okay so I have an older model Speco Technologies DVR System that has 16 channels (cameras) it currently has a 500GB IDE Hard Drive in it, I am very familiar with computers and desktops, as well as taking them apart and putting them back together. I didn't even think twice when I ordered a new 2TB SATA Hard Drive to add to the DVR System as to allow more storage for recording time. The old Hard Drive is an IDE and the one I ordered is a SATA. There are already ribbons and cables for a secondary IDE Hard Drive, there is also a power cable for a SATA but no Data cable for the sata as it is the old IDE Ribbon that is already with the machine. I want to know if I buy the converter (the IDE to SATA converter) will it accept the SATA Hard Drive, or will it reject it? also I would be leaving the existing IDE Hard Drive, just adding the SATA along with it. I can send the SATA HDD back to disctech, although the largest IDE/PATA HDD they have is 500GB when I really want a few TeraBytes instead. I can't load the cctv forums their website is down or something. I just need to know if the adapter will suffice or if it's not even worth odering the adapter and playing around waiting when I only have 30 days to return the SATA HDD I just bought. Also could I just buy a SATA data cable and use that along with the SATA power cable that is already provided in the DVR ( I don't know why it has the IDE ribbons/power cord as well as a random SATA power cable without the SATA data cable) (unless it was for the hbyrid IDE/SATA/PATA Hard Drives) I'm at a loss and I need help, anyone who can help I really truly do appreciate your response and opinion. Thanks