Choosing a password
Open Source OS on Intel Mac
BSD and Linux on an Intel Mac
Thanks to Glen Barber for this article, which was my primary source of information.
There are a lot of perfectly good Macs out there that have been rendered obsolete by Apple, since the latest versions of OS X will not install on them. While security is not as big a concern for OS X users as it is with Windows, it's still not a good idea to browse the web using an OS that's no longer receiving security updates.
Running an open source OS such as one of the many BSD or Linux distributions can breathe new life into your older Mac.
Not only will it allow you to run a fully updated and secure OS, it might also be notably faster than OS X. As of December 2018, I am running the latest FreeBSD 11.2 on a 2007 iMac Core2 Duo 2.0 GHz, and performance is quite good - much faster than OS X on the same machine.
If you have a relatively recent Mac, running a recent BSD or Linux system should be relatively easy. I recently installed FreeBSD 11.2 alongside OS X El Capitan on a mid-2009 iMac. Installation went smoothly and it boots without the help of any special software. Just hold down the Option/Alt key on boot and select if from the available boot drives.
Installing FreeBSD or Linux on an older Intel Mac can be a little tricky. Apple makes major changes to the EFI BIOS and tools like Bootcamp, rendering many of the instructions you might find on the web obsolete.
Below are instructions I've used with success to install FreeBSD 10.2 through 11.2 alongside OS X on a mid-2007 iMac. Installing FreeBSD as the sole operating system is more challenging, since you may need a boot manager such as rEFIt that resides on the OS X partition.
Basic installation of FreeBSD onto a partition alongside OS X is a snap. The tricky parts are getting the partition created in the first place and then getting the Mac EFI firmware to boot it.
I've had mixed results getting Boot Camp to recognize a FreeBSD partition. It works on my 2007 MacBook Pro, but not on my 2007 iMac.
To use rEFIt, just install following the instructions at the rEFIt link above. To activate it, you must then run the following command from a Terminal window:
When you reboot, the rEFIt boot menu should automatically appear.
Insert the FreeBSD install CD/DVD before rebooting and simply select it from the rEFIt menu. From here, installing FreeBSD should work exactly as it does on any other PC with another operating system installed and the new FreeBSD installation should appear in the rEFIt boot menu after the next reboot. Be aware, however, that it may appear as a Windows icon by default. This is not a problem. Just select it anyway, and FreeBSD should boot normally.
Partitioning the Disk with Boot Camp
Boot OS X and run Boot Camp Assistant.
With newer versions, you will need to insert a Windows 7 installation DVD, or Boot Camp will not allow you to partition the disk. Find a Windows 7 installation DVD, insert it, click Continue and partition the disk as you like. When Windows installation begins, just cancel it and reboot.
After reboot, eject the Windows DVD and insert the FreeBSD DVD.
Partitioning with Disk Manager
You can also partition the disk using Disk Manager (in the Utilities folder under OS X). Select the disk and choose the "Partition" tab. You can now shrink your OS X partition by grabbing the lower right corner and dragging it up. This may fail if you try to shrink it too much, due to fragmentation of the HFS filesystem.
To boot the FreeBSD installation disk, you can either hold down the Option key to get to the Boot Camp boot menu, or if you've installed rEFIt, just let the system boot to the rEFIt menu. Either way, select the FreeBSD installation disk from the menu.
Now comes the easy part. Just follow the normal FreeBSD installation procedure, with attention to the instructions below.
Reboot and your FreeBSD installation should appear in the Boot Camp or rEFIt menu.
You may also need to allow rEFIt to update your MBR table before it will boot the FreeBSD partition. Choose "Start Partitioning Tool" in the rEFIt menu, and it will tell you if the MBR needs to be synchronized.
In theory, the process should be similar for other BSDs and most Linux distributions, although my most recent attempt to install Debian 8.2 ended with the boot loader freezing.
There was a regression in the Apple Touch Pad driver that causes the touch pad to stop responding as the computer warms up. If your system exhibits this system, this script should fix it, provided you have the FreeBSD source code installed.
This script can be used to remap the lower-right "enter" key to a Ctrl key and the right "Command" key to another Alt/Meta key for your Xorg session. Edit to taste...
The following sysctl settings greatly improved performance for the ATP driver on my 2006 white MacBook:
hw.usb.atp.scale_factor=10 hw.usb.atp.touch_timeout=50000 hw.usb.atp.double_tap_threshold=100000