Booting Options for Macintosh Computers
Around 2000, Apple began using new firmware in their Macintosh computer systems called Open Firmware. Firmware on the Macintosh is analogous to a PC’s BIOS in many ways. Older Macintosh systems that contain Motorola 68K or “Old World” PowerMac firmwares have tremendous differences in their firmware. This article does not cover those machines. Macs with later G3, G4, G5 and Intel Core™ processors have the Open Firmware we are discussing here.
These “New World” machines have some new abilities. Open Firmware is based on the IEEE-1275 standard and is non-proprietary and computing platform independent. To gain access to Open Firmware on your Mac, you press the cmd-opt-O-F keys just as you power up the Mac. When finished using Open Firmware, you can reboot by typing: mac-boot
Ah you say, but what are the booting options you speak of in the title of this article? There are many items I would like to discuss briefly about “New World” Mac boot options. These include the option of target mode, netboot, optical drive boot and system selection mode.
Target mode was introduced prior to “New World” machines with a specialized SCSI target mode in older machines. The new target mode today allows a Macintosh to be turned into a slave hard drive to another Macintosh. Holding down the T key as a Macintosh is booted will enable target mode. The slave Macintosh will flash a target mode symbol on screen to let you know that you are in this mode. Macs with an “Open Firmware Password” enabled WILL NOT go into target mode.
Booting your Mac from its optical drive is especially important for reinstallation of software from CD or more commonly DVD. Press and hold down the C key will powering up your Mac to boot from the CD or DVD drive on your Macintosh.
Another option, is to perform a NetBoot on a client Macintosh. NetBoot allows you to start up a Macintosh computer from a network disk image rather than the local hard drive. This is most common in a large network environment like businesses or schools. Holding down the N key while booting your Macintosh will enable NetBoot. The Mac will use NFS and TFTP protocols to find a NetBoot image and startup.
System selection mode (system picker) is enabled on Macintosh boot by holding down the Option key. A simple graphical interface will allow you to pick from multiple source operating systems across multiple sources including CD, DVD, hard drive, optical drive, and network images. With Apple’s BootCamp, this method is used to select the Windows OS to boot.
In our next installment on “Booting Options for Macintosh Computers” we will discuss password protection, single user mode and verbose modes. See you then.
This article was written by Perry Lund on Saturday, March 15, 2008. Permalink.
March 23rd, 2008 at 6:57 pm
Nice, this is exactly the information I was looking for in simple terms, thanks!