deb http://archive.ubuntu.com/ubuntu/ intrepid-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ intrepid-updates main restricted universe multiverse
#deb http://archive.ubuntu.com/ubuntu/ intrepid-proposed main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ intrepid-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ intrepid main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ intrepid-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ intrepid-updates main restricted universe multiverse
#deb-src http://archive.ubuntu.com/ubuntu/ intrepid-proposed main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ intrepid-backports main restricted universe multiverse
这些源中 的 restricted universe multiverse 都代表什么？
这些又都代表什么呢？
intrepid-security
intrepid-updates
intrepid-proposed
intrepid-backports
google没有找到答案，希望哪位高手为我们这些菜鸟普及一下
