Using the Classic Environment is generally pretty simple, and doesn't require a lot of tweaking and twiddling. However, the Classic Environment does have a few of its own settings, as well as a few tools for monitoring it. These are found in the Classic pane of System Preferences.
The general preferences for the Classic Environment are located in the Start/Stop tab; for most uses, this is the only tab you'll need to worry about. As I explained earlier, when you launch Classic, it loads an entire iteration of Mac OS 9. (In fact, when the Classic launch screen appears, if you click the triangle next to "Show Mac OS 9 desktop window," you'll see what looks like a Mac OS 9 startup screen, complete with the icons of OS 9 extensions as they load.) However, first you need to tell it which Mac OS 9 System Folder you want it to use. You do this in the box under "Select a system folder for Classic" (Figure 8.1). Each mounted volume is listed; if a particular volume has a valid Mac OS 9 System Folder installed, it is selectable. If a volume has more than one OS 9 System Folder installed, click the disclosure triangle to the left of the volume name to view them all. Select the desired volume or, if the volume has multiple System Folders, the desired System Folder, and the appropriate System Folder will be used by Classic the next time it is launched.
Figure 8.1: The Start/Stop pane of Classic preferences
If for some reason you boot between Mac OS X versions (for example, 10.1 and 10.2), note that once you've used a Mac OS 9 System Folder in Classic under OS X 10.2, it will no longer work under OS X 10.1's Classic Environment. (In general, it's safe to assume that this will apply to newer versions of Classic in Mac OS X, as well—once you use an OS 9 System Folder in a newer version of Classic/Mac OS X, it won't work with older versions.) Thus if you need to switch between versions of Mac OS X, I recommend having a different OS 9 System Folder for each Classic Environment.
If you're having trouble selecting a System Folder or volume for Classic, I've included a few solutions later in the chapter under "Classic Trouble."
In general, there are three ways to launch Classic. The first, and easiest, is to simply launch any Classic application; the Classic Environment will automatically launch and load OS 9, then the application will be launched from within Classic. The second method is to check the "Start Classic when you log in" box in Classic preferences, which automatically launches Classic at login. The third way is to manually click the Start button in Classic preferences, which launches Classic immediately; after it's done loading, you can launch your Classic application(s). Although the first two methods are convenient, at the time of this writing they both seem to generate a fair amount of complaints and reports of problems. Therefore, I recommend that you just launch Classic manually when you need to use it. (A bit later in the chapter, in "Using Classic," I show how to do this from the Dock or using third-party apps so that you don't have to open System Preferences every time you want to use Classic.)
If Classic is running, the Start button changes to Stop. Clicking this button is identical to choosing the Shutdown command in Mac OS 9; all Classic applications will quit (you'll be able to save changes first), and then the Classic Environment will shut down. Likewise, the Restart button functions just like the Restart command in OS 9 (a shutdown followed by an immediate startup). Note that this Shutdown command affects only the Classic Environment, not Mac OS X. The third button, Force Quit, works exactly like the various force quit commands I discussed in Chapter 7, except that it immediately, and ungracefully, quits the Classic Environment and all Classic applications. You would use this command only when the Classic Environment crashes or freezes and you can't use any of your Classic applications. (Keep in mind that you'll lose any unsaved changes in Classic applications.)
The last option in the Start/Stop tab is "Warn before starting Classic." This option, new as of OS X 10.2, will warn you if you launch a Classic application and the Classic Environment isn't already running. If you used earlier versions of Mac OS X, you've probably experienced the frustration of accidentally launching the Classic Environment via inadvertently launching a Classic application (for example, by double-clicking on a document associated with a Classic application). You could click the Stop button in the Classic startup window, but Apple recommended against this. When this option is checked, before Classic is launched, you'll get a dialog asking if you really want it to (Figure 8.2).
Figure 8.2: The "Warn before starting Classic" dialog
The Advanced tab of Classic preferences has a few additional options associated with the Classic environment. These are mainly "set and forget" preferences and options that you would use when troubleshooting.
When booting up your computer under OS 9, you could select several options, such as booting with extensions disabled, opening Extensions Manager, or holding various keys down to invoke other options or third-party utilities. Under Startup Options, you can access the same options when starting up the Classic Environment; just select the corresponding action from the pop-up menu and then click the Start Classic button (or Restart Classic if Classic is currently running). If you choose Use Keyboard Combination, a box will appear allowing you to designate the keys you want to be "pressed" as Classic is launched.
Why would you want to use these options? Remember that Classic loads a full version of Mac OS 9; just as you can have startup file conflicts in OS 9, so too can those kinds of conflicts occur in Classic. Just as you can use Extensions Manager (or similar utilities like Casady & Greene's Conflict Catcher, http://www.casadyg.com/) to manage startup files when booting into OS 9, so too can you manage startup files in Classic. (I'll talk more about this later in the chapter when I discuss optimizing Classic.) This option is a one-shot deal—it only affects the single startup or restart initiated by clicking the Start/Restart button in this tab.
The "Use preferences from home folder" option allows each user to have their own preferences for Classic applications. Under pre-10.2 versions of OS X, Classic applications each had a single preference file, shared by all users, located in the Preferences folder of the System Folder used by Classic. Under OS X 10.2 and later, if this option is checked Classic applications store their preferences in each user's /Library/Classic/Preferences folder.
If you have "Use preferences from home folder" enabled, the first time each user launches Classic the following folders will be created in their home directory (under ~/Library/Classic): Apple Menu Items, Internet Search Sites, Launcher Items, Preferences, Shutdown Items, Startup Items. In addition, if they exist in the Classic System Folder, these folders will also be created in the home directory: Desktop Pictures, Favorites, Keychains, Locations, Shutdown Items (Disabled), Startup Items (Disabled), Volumes. The user will be asked if they want the contents of the corresponding folders in the Classic System Folder to be copied to their home directory. (One consequence of not allowing this copy is that the Chooser will not appear in the Apple Menu, meaning the user won't be able to print from within Classic.)
When Classic is running, it takes up a good deal of system resources (RAM, CPU time, etc.). You can set the Classic environment to "sleep" after the amount of time you set in this section (provided no Classic applications are running); when Classic is sleeping, it uses virtually no system resources. However, many users have reported problems with Classic when using this option; when waking from sleep, the computer can freeze, or certain hardware functionality (e.g., the USB port) may no longer be accessible from Classic. I recommend setting this option to Never—if you can't spare the RAM, you're probably better off quitting Classic when you aren't using it.
The Rebuild Desktop button allows you to manually rebuild the Desktop database files used by Classic and Classic applications to associate documents with applications. This database is only used by Classic; it will have no affect on Mac OS X.
The Rebuild Desktop command only rebuilds the Desktop database files for the volume that contains the Classic System Folder. In order to rebuild the Classic Desktop databases for all mounted volumes, you need to use a procedure similar to that used in OS 9: use the "Use Keyboard Combination" options, and select command+option as the desired keyboard combination. When Classic has almost finished loading, this will bring up the standard OS 9 dialogs asking you if you want to rebuild the Desktop for each volume. (As a bonus, Classic can rebuild them simultaneously, rather than one at a time as OS 9 generally does it.)
The Memory/Versions tab of Classic preferences doesn't really contain any preferences; it is instead a way to monitor Classic and any running Classic applications. The bottom of the window provides information on the version of Mac OS 9 being used by Classic, the versions of the Classic support files installed in the Mac OS 9 System Folder (discussed below), and the version of the actual Classic Environment application.
The Active Processes box shows any Classic applications currently running, along with their memory usage (Figure 8.3). This is similar to what you would see in the "About this Computer" box in the OS 9 Finder. If you check the "Show background processes" box, you'll also be able to view any background applications running in Classic.
Figure 8.3: The Memory/Versions tab of Classic preferences