You are most likely used to using your computer to do something, and to do that, you need to run processes. While at this point you could have your computer launch a shell, you would still have a lot of setting up to do such as mounting hard drives, bringing up your network adapters, starting services, launching a GUI or what ever else you want to do. This is tedious and beyond the ability of most people so instead of running a shell the first process your computer runs is some kind of process manager. Traditionally this has been the init program which is the parent of every process that is executing.

Init is controlled by a handful of scripts that in turn ...

My filesyserver at home is a opensolaris box using raidz under zfs and right now it is having some problems. Recently I had to replace a drive that did not fail but it was making some clicking noises. After repplacing it the first resilver left me with an error about a snapshot that i didn't need being damaged. okay i can live with that, so i just need to delete the snapshot and bring the pools redundancy back up. well, it reslivered everything, but it didn't seem like the pool was running completely. i cleared the error and it started to resilver again. same thing happened again but now i am getting a warning for something else <0x5c>:<0x64d62> and now the resilver is going past 100% and copying more then the amount of data i have. some posts online suggest disabling snapshots because they are keeping it from completing. didnt work so i reboot the computer and when it comes back online it starts resilvering automatically. again it goes to 100% and keeps working but this time it takes two files with it, the one before and <0x2b3>:<0x64d62>. looking to another post i see to upgrade ...