Ubuntu: suspend and hibernate

Self-tutoring about home computer use with Ubuntu Linux: the tutor mentions suspend and hibernate.

The following is according to my understanding.

A few months back I resurrected this old computer, which is maybe from 2017. Its battery might be weak; I’m testing it out today.

Earlier, at 79 percent charge but unplugged, I had to leave it to do some chores. Yet, I wanted to see how its battery would hold up being idle for a few hours. I looked at the Leave options down in the left. One was Suspend; I wasn’t sure what that meant.

Apparently, Suspend stores your session details in RAM but not on disk, so you can resume more quickly when you return. To save power, it turns the screen off and maybe some other things.

To me, Suspend in Ubuntu sounds like Sleep in Windows 7. (About that, see my post from June 25, 2017.) Moreover, both Ubuntu and Windows 7 seem to share the idea of Hibernate, which saves the session details to disk before going to an even lower-power state.

As I understand, Hibernate takes longer to awake from than Suspend, but if the computer loses power altogether during Hibernate,the session details have been saved to disk. However, if the computer runs out of power during Suspend, the session details are lost, since they were in RAM but not on disk.

I left this computer suspended, unplugged, for about four hours. It lost about 12 percent of battery charge during that time.

Source:

Ubuntu Manpage: pm-action