Student or Learner
dear sir in this sentence
perform catch-up maitenance if the computer was not running .
i don't understand catch-up maitence
catch-up maintenance - all the maintenance that one has not done, but has to do in order to have all the maintenance complete that should be complete up until "now"
It's usually "catch up on" or "catch up with".
They had a lot of work to catch up on after being away for so long.
In your sentence, "catch-up" is a compound adjective. It refers to the same idea as the phrasal verb "catch up on" or "catch up with".
Here's another way to use "catch up".
Joe waited for Karen to catch up with him. When she did, they continued walking. (Joe was further ahead. Mary was behind, so she had to "catch up".)
If you're "behind", then you have to catch up.