Are there guide lines to follow when you have a large harddisk (i.e. 100 GB in the PowerBook)? A partition for the system and applications and another partiton for everything else? What should the max. size of a partition be?
It all depends on how you want it -- some people are going to tell you not to use partitions, and some are going to tell you to use partitions, both for different reasons.
- you can move data to a partition other than your boot partition... if your OS dies, your data is intact on a different partition. If your hard drive dies, you lose all partitions
- you can organize more effectively, much like having multiple disks... one partition for the OS, one for data, one for client's projects, etc.
- you can make a small, emergency boot partition that you can boot from in case of OS errors to run a thorough check on the affected partition
- multiple partitions do not provide any kind of speed increase by moving swap files, home folders, etc., contrary to belief
- it's complicated
- you can run into "gotchas" that require wiping the whole drive anyway, like making your boot partition too small then running out of room later
- it's better to leave OS X pretty much alone and not move certain folders from their default locations... you can back up your home folder on a DVD most times, and moving folders around sometimes confuses OS X
Anyway, these are just things I've heard. If you do decide to partition, make sure you make your boot drive big enough to grow as needed... if you intend on installing iDVD or GarageBand and leaving their gigabytes of support files in the default install locations (on the boot drive), that can take up 6 to 8 GB of space... I would recommend at least 30 and preferrably 40 GB.
On a pc, it's essential, for me, to partition drives as it is easier and safer to have my programs and data separated. I can backup my data partitions easily and if Windows dies I can easily re-install/restore without too much fuss and get going again quickly.
Plus I have my pagefile (swap) on it's own partition as it gives a good speed boost, controls defragmenting and is a good indicator of overall health of the disc. (ie if the pagefile partition starts to have bad cluster errors then I know I have time before the rest of the disc displays errors. An early warning system of sorts!)
On a mac, I don't bother as my home folder acts as a visual 'partition' so it's simple to back up (and restore if necessary.)
This is one of the reasons I 'switched' almost everything is easier on a mac.