Note: This article pertains to Mac OS X Server versions 1.x, which were released prior to May 2001.
Mac OS X Server and Mac OS 8.x or Mac OS 9 can be installed on the same computer, and you can choose the OS you want to use to start the computer.
Most Power Macintosh computers (and iMacs) load a small program called Open Firmware when they are first turned on. Open Firmware determines where the computer's startup device is (such as a disk) and which file on that device is used to start up the computer (such as Mac OS 8).
Some of the settings used by Open Firmware can be changed using a utility program that runs in OS 8.x and OS 9 called System Disk. It is located on the Mac OS Extended format (HFS Plus) partition of the Mac OS X Server CD-ROM disc in the Utilities folder.
Note: You cannot select a Mac OS X Server disk as your startup disk in the Startup Disk Control Panels in Mac OS 8.x or OS 9.
The System Disk application contains an icon list of disk partitions available to the computer labeled with the kinds of operating systems installed on each partition. At a minimum, the System Disk application will contain options for "Open Firmware" and "Mac OS" on the computer's hard disk. If the Mac OS X Server CD-ROM disc in the drive, you'll also see the partitions and versions of system software available on the disc. Additional partitions may also be listed if you have attached additional storage devices to the computer.
In the System Disk window, Mac OS and Mac OS Extended format partitions appear with a Mac OS badge on their icons, and Mac OS X Server partitions appear with an "X" badge on their icons.
To select the startup OS and disk, follow these steps:
1. Open the System Disk application. This program is provided on the Mac OS X Server disc within the Utilities folder.
2. In the list of devices, select the volume that will start up the computer.
3. Click Save and quit the application.
4. Restart the computer.
The computer will now start up from the volume that you selected.
Using the System Disk utility program in this way, you can easily switch between the two operating systems.
If you expect to frequently switch between systems, you may want to install the Mac OS 8 System Disk extension (located in the same folder as the System Disk utility program on the Mac OS X Server disc). When this extension is installed, holding down the Option key during startup opens the System Disk utility program and allows you to choose the partition and OS you want to use.
If Mac OS X Server is set as the computer's default OS in Open Firmware, holding down the Option key until the Happy Mac icon appears stops the computer from starting up with Mac OS X Server, and makes the computer start up with Mac OS 8 by default (if Mac OS 8.x or Mac OS 9 is installed on an available partition). Holding down the Option key longer than this during startup will open the System Disk utility as described above.
Resetting the Parameter RAM (PRAM) (Option-Command-P-R) at startup is another way to reset Open Firmware's settings to start up with Mac OS 8 or Mac OS 9.
For instructions on formatting a hard disk for use with both operating systems, see article 60175: "
Where Should the Mac OS 8 Partition Be Located?"
If you have OS X Server and Mac OS 8.6 or Mac OS 9 installed on a Power Mac G4 or a Macintosh Server G4, you can also select the OS and disk from which the computer will start up using the Startup Manager. For instructions on how to use the Startup Manager, see article 106178: "
Startup Manager: How to Select a Startup Volume"