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alex_free

macrumors 65816
Original poster
Feb 24, 2020
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Goal - Install Mac OS 9.0 and the latest OpenBSD 6.6 on one 3GB HDD in the iBook G3 Clamshell.

Mac OS 9 does not take up much space, and neither does OpenBSD (espically compared to some Mac OS X versions). So both systems could work on just 1.5 GB partitions.

On Mac OS, usually you can install apps to external USB drives as the internal HDD fills up. But once you really start doing anything on OpenBSD like installing pkgs, getting the source and ports tree, etc 1.5GB is not going to work. So instead I created a /usr partition on a 32GB USB flash drive. The worst part is the USB 1.1 speeds, but having enough space to do real work is worth it.

System
-iBook G3 Clamshell 300 MHZ, 3GB HDD, 544MB RAM, Airport Card.
-32GB USB Flash Drive
-Mac OS 9.0 and OpenBSD 6.6 CD-Rs. It is best to use the oldest CD burner available to create these CD-Rs. The iBook CD drive can't read CD-Rs made by my cheap new USB burner, but can read CD-Rs made by a Mac mini G4.

Requirements
-Mac OS 9.0-9.2.1 Installer CD
-OpenBSD macppc Installer CD

Optional
If using a USB drive for the /usr partition, it must be formatted as Apple Partition Map and Mac OS Extended in either Mac OS 9 or Mac OS X.

1) Setup Mac OS
Place the Mac OS 9 CD in the drive and reboot while holding down the c key. In the Utilities Folder open Drive Setup. Select the HDD, click 'Initilize' - 'Custom Setup...'. Create 2 Mac OS Extended Partitions and click 'Ok' - 'Initilize'.

Once done in Drive Setup, open 'Install Mac OS'. Select the first partition created earlier. After installation, reboot into Mac OS. In Mac OS, swap the Mac OS 9 Installer CD for the OpenBSD 6.6 macppc Installer. Open the OpenBSD Installer in Finder and copy the file 'ofwboot' to the Mac OS 9 partition in the root directory. Select OpenBSD as the startup disk and reboot.

2) Setup OpenBSD
After OpenBSD completes booting go through the installer. Setup WiFi, system name, users, etc. until asked about root disks. The Apple Partition Map Mac OS Extended USB drive is sd0, the internal 3GB HDD is WD0. Use wd0, then specify HFS partitioning when asked.

Modify the disk when asked, and enter the p command to print the partitions. I found the second Mac OS Extended partition on WD0 at partition 10, so I entered the 'd' command and specified for partition 10 to be deleted. Next I entered the 'c' command and specified the base of the original partition I had just deleted. After that specify the length of the same partition. Name the partition 'OpenBSD'. Execute the 'w' command and confirm you want to make the changes. Then execute the 'q' command.

Optional - Use A USB Drive For /usr
When asked what disks you want to initialize, enter 'sd0'. Select HFS partitioning, and create an OpenBSD partition exactly as was done on 'wd0'. Once done, you will escape to yet another shell. This one has different commands, execute 'd a' to mark the first partition as deleted. Then execute 'a a' to create a new a partition. Keep the default offset and filesystem, for size I entered 28G for a 32GB USB drive. Specify mount point as '/usr'. Execute 'write', then 'q' and wait for the format.

Continue in the installer as normal.


3) Fix Mac OS Booting
After installing OpenBSD, the Mac OS 9 partition will stop booting. You'll get a blinking floppy ? icon until eventually your Mac will auto power off.

To fix this, swap out the OpenBSD CD for the Mac OS one and boot holding the c key down. Then open Drive Setup, and select the HDD. Click 'Functions', and in the drop down menu click 'Update Driver'. After it completes, reboot. The Mac OS 9 partition is now bootable again.


Mac OS will boot by default. To boot OpenBSD hold down the command+option+o+f keys all at the same time while powering on the Mac until it boots Open Firmware.
At the prompt, execute the command 'boot hd:,ofwboot /bsd'.
 
Last edited:
oooo... good idea! :D

What would change in the install guide if I were to do that? Also, is the flash drive only used if you want to create a /usr directory there?

Yea I’m only using the flash drive for more space on /usr. The only thing that would change is add more partitions initially.
 
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Yea I’m only using the flash drive for more space on /usr. The only thing that would change is add more partitions initially.
Ok, thanks! I very well may do the install then! :D

I might not do it right when I upgrade the SSD, as I'll need practice installing OpenBSD, but I want to do it definitely! :)
 
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It's guides like this that make me wish the iBook had an easier to access HDD bay. I'd love to try this out, but I want to keep my eventual OS 9/OS X setup

There are easier ways to get at the hdd bay. There's a youtube video to show you how, you have to bend back the aluminum shield thing in there, but it saves you having to completely disassemble the machine.

Edit:

2nd method:
 
Last edited:
There are easier ways to get at the hdd bay. There's a youtube video to show you how, you have to bend back the aluminum shield thing in there, but it saves you having to completely disassemble the machine.

Edit:

2nd method:

I don’t like the 1st method, but the second method I think I’ll actually use. At some point the 20 year old hard drive will need replacing, thanks.
 
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