|Before beginning the install, make sure you read the Apple-provided booklet, and any "Late breaking" files you find on the CD. These contain important information, and should not be skipped. Once youre done reading, its time to think about how youre going to install OS X.
One key decision that needs to be made is "to partition or not to partition?" (if you have a spare hard drive, the question is whether you wish to manage two unique System 9.1 folders or not). Partitioning is (in a gross over-simplification) a means of making one hard drive appear to the system as two or more unique hard drives. The advantage of a partition is that you can wipe all the data off of it without losing everything else on the hard drive, and that you can keep two completely independent systems to use at your discretion. Partitioning needs to be considered with OS X because, for quite a while, youll actually be running two operating systems OS X and OS 9.1. OS 9.1 is needed to run those applications that have not been upgraded for OS X, so it plays a key role in using the new system.
If youve been using the Public Beta, I recommend removing it entirely. Hopefully its on a separate partition, and you can simply erase the volume and start fresh. If its on the same volume as OS 9, search macosxhints for the "remove OS X" article for instructions on how to get rid of all of the beta. You can theoretically install over the PB, but I figure thats one more variable I can easily eliminate.
Heres a quick look at two installation options, and the pros and cons of each as I see them.
1) Install OS X over your existing OS 9.1 folder on a one-partition hard drive.
This is certainly the easiest way to install OS X. The primary advantage is that you dont need to worry about keeping two (or more) versions of OS 9 system folders in synch if you install applications, fonts, tweak preferences, etc. Everything is in one spot.
The primary disadvantage is that if you boot back into OS 9 very often, youll spend a lot of time playing with the Extensions Manager. Classic works best with a minimal (or none) set of extensions most of the work is done by OS X. I currently boot Classic with just the extensions necessary for Microsoft Office98, and thats it. But when you boot into 9.1, youre going to want your full extension set to take advantage of your peripherals. So youll have to switch the startup disk, reboot, open the extensions manager, change to the full set, and then let the boot process complete. Not too bad, but one extra step each time you boot.
Also, if you dont trust OS X with your disk, you may not want to have it writing certain files into your OS 9 system, which it will do in order to support Classic. I would install this way only if you dont plan on booting into OS 9 very often, and have a high degree of confidence in OS X 10.0. If you can at all spare the space, the preferred method (although its more work up front and more of a pain to keep everything in sync) would be option two.
2) Install OS X and a new 9.1 on a separate partition (or hard drive)
This is the most flexible install method, and the one that I have chosen to use. I keep a clean OS 9.1 drive (my large, 45gb hard drive) for booting with a full load of extensions (scanner, camera, SCSI CD-R, tape backup, etc.). On my second partition, Ive installed OS X and a fresh copy of OS 9.1 from the OS X retail package. This is the drive I will boot from most of the time. When I need to boot into OS 9.1, I simply switch the startup disk system preference and reboot. No mussing around with extension sets is required, and OS X will not modify my clean OS 9.1 volume.
To make this work, you need to either have a spare hard drive or partition your existing drive. If you choose to partition your existing drive, you must back up your data before you start!! Creating a new partition map will destroy all the data on your hard drive! Partitioning is beyond the scope of this review, but it is handled through the Drive Setup program that ships with all copies of the Mac OS. There are lots of good resources on partitioning, and I urge you to read up on it before you proceed.
Assuming you have the partitions created, simply install OS 9.1 with as few extensions as possible, and then install X on top of the new 9.1 install. When I installed 9.1, I left out major portions of the system that I felt were unnecessary to Classic things like QuickTime, Speech Recognition, Internet Apps, etc. I may have to go add a few back, but for now, its working fine. Make sure you go to the Classic setting in the System prefs area (after you install OS X) and tell Classic which OS 9 volume to use. Point it at your newly installed Classic, not your fully loaded one on the other drive/partition.
The biggest downside to this installation method is the management of prefs and folders that are usually installed in the System folder. For example, Eudora keeps a mail folder ("Eudora") in the top level of the System 9 folder. To make sure that I could read email in Classic Eudora from either my real 9.1 or my OS X Classic environment, I created an alias of the Eudora folder from my real 9.1 drive, and placed it in the System folder of my Classic 9.1. Now, I see the same messages in both environments. Its a bit trickier with a carbonized application like Internet Explorer. I made aliases of my "favorites.html" and "history.html" files from the real 9.1 system (located in System -> Preferences -> Explorer), and placed them on the OS X drive, in the path:
Now when I add a bookmark or visit a new site, only one history file is updated, and I only have one set of bookmarks to worry about. Similar tactics will have to be used as other apps are Carbonized.
Multiple system folders can also make it tough if you use many packages that check for a key in the prefs file, as youll have to re-install or re-enable many of your apps if you launch them in Classic.
Overall, however, I think the added safety of having OS X on its own partition is worth the trouble it causes in the short term.
NEXT - The Install!