mac osx: keyboard shortcut to lock screen

mac desktop keyboard:  ctrl-shift-eject
macbook keyboard: ctrl-shift-fn-power

above two sleep the screen.

below put to sleep the machine:
opt+cmd+eject

linux mint formats 3TB hard drive to NTFS

1. installed GParted if not yet got it.
2. create partition table (this is very important!), choose GPT instead of msdos (which has a limit of 2.2 TB)
3. create the partition as NTFS, primary partition.

done.

GPT is common table that is readable by most linux-based embedded devices too.