Mac OS X — do not wake up disk after computer wake up

I think your best bet would be to set the drive to only be mounted manually. I imagine there is a GUI way to do this in OSX but the following, UNIX, approach should also work.

Edit the file /etc/fstab and look for the line mounting the relevant drive. Should be something like:

UUID=a180cec0-xcad-4344-2e19-7b0249ef23b0   /Volumes/foo    hfs rw,auto 0   0

The first field is the disk name or UUID, the second is the mount point, third is the file system and fourth is the options. The last two are for integrity checks and can be ignored for now. Remove auto (if present) from the options field and add "noauto":

 UUID=a180cec0-xcad-4344-2e19-7b0249ef23b0  /Volumes/foo    hfs rw,noauto 0 0