pm - 一時停止 - ハイブリッドとは何をしますか？

man 説明する

   pm-suspend
       During suspend most devices are shutdown, and system state is saved in RAM. The system still requires power in this
       state. Most modern systems require 3 to 5 seconds to enter and leave suspend, and most laptops can stay in suspend mode
       for 1 to 3 days before exhausting their battery.

   pm-hibernate
       During hibernate the system is fully powered off, and system state is saved to disk. The system does not require power,
       and can stay in hibernate mode indefinitely. Most modern systems require 15 to 45 seconds to enter and leave hibernate,
       and entering and leaving hibernate takes longer when you have more memory.

   pm-suspend-hybrid
       Hybrid-suspend is the process where the system does everything it needs to hibernate, but suspends instead of shutting
       down. This means that your computer can wake up quicker than for normal hibernation if you do not run out of power, and
       you can resume even if you run out of power. s2both(8) is an hybrid-suspend implementation.

説明を見ると、最後の項目が最初の2つの項目とどのように関連しているかがわかりません。たとえば、電源がなくても動作し、ディスクに保存することはできません。

ありがとうございます。