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A/UX 3.0 installation and multi-boot configuration

These are my notes to myself and those who are interested in setting up their systems to boot A/UX and "something else." A/UX has some drawbacks as a primary OS, and being able to dual-boot or triple-boot or whatever greatly increases its utility.

Warning: These are the steps that worked for me. If there is a better way of doing something, I'd like to know about it. These steps are not based off any Apple documentation.

Double Warning: A/UX is still a copyrighted product owned by Apple. If you have an A/UX system for which you need replacement installation media, you can check Gamba's download page for a list of places to download Macintosh operating systems, including A/UX.

Triple Warning: Before you embark on this, make sure your Mac is a supported model, and that you are using a supported CD-ROM (if it is an Apple ROMmed CD-ROM, it has an excellent chance of working; I have installed from an external CD 300 and an internal Apple 24x SCSI drive stolen from a beige PCI Power Mac). If the installer doesn't find the CD, you will be hosed.


Normally, there are several partitions on an A/UX disk: the MacPartition, which actually boots the machine; the UFS root partition, which actually has the kernel and is booted by the MacPartition; a swap partition; and an Autorecovery nee Eschatology partition, which is supposed to be a repository for critical files during system recovery but in my experience and the experience of others really serves the purpose of being a disk space black hole.

The partitioning scheme I prefer has two HFS partitions: one for the MacPartition, and then any number of standalone HFS paritions on the side to use your favourite extensions without messing with the MacPartition's system folder and causing trouble. (You can also install other system versions here without hurting A/UX.) I also don't bother with the Autorecovery partition, since even if it did (does) work, it has little functionality that a good fsck doesn't.

The disk partitioner you will use during the A/UX setup will allow you to seemingly create nice fat partitions which may not work when you try to actually install A/UX to them. More to the point, A/UX cannot be safely used on partitions larger than 4GB under any circumstances, and filesharing is risky above 2GB, mostly due to inherent limitations of System 7.0.1. So:

If your disk is 4GB or smaller

Congratulations, you have lots of flexibility, because the partitions you create should "just work" and the A/UX driver will be satisfactory. My IIci A/UX booter was built in this manner on a 1GB Seagate Hawk drive. You will need a copy of HDSC Setup 7.3.5 for the first portion of this -- don't use A/UX's. I like the patched version on Gamba's hard drive page. This assumes you have some familiarity with Apple's hard drive partitioning utilities. Boot from your HDSC Setup-enriched boot floppy.

Now boot A/UX with the boot disk and A/UX install CD. Go to Custom Install and Step 1 (to continue partitioning).

Thus endeth the Partitioning.

Step 2 of the Custom Install puts the MacPartition boot files on the MacPartition. Start this step and make sure it chooses your MacPartition, not your locked MacOS partition which you will reserve for your beloved MacOS. This is very fast, typically.

Step 3 of the Custom Install installs the actual guts of A/UX. It should find your "root & usr" filesystem and chuck everything on it without further preamble. Pick the filesets you want installed.

If your disk is larger than 4GB

If you have a large disk, you may get better performance from an alternative disk driver, and some people have reported that the boot driver can get confused if the startup volume is too far away from the driver partition. If you notice that the wrong volume is starting up than the one you selected (and you're sure your PRAM isn't scrambled and your PRAM battery is good), then you are bitten by this bug and you need another driver. Note that no Apple-ROMmed drive that came with any 68K Mac was anywhere near this size, so this wasn't a problem back in the day. Also, make sure you are using an upgraded Startup Disk CDEV, see below.

The driver I recommend for big disks is LaCie Silverlining 5.8.3, which is A/UX aware and comes with lots of LaCie devices (it is not hard to find used). I don't know if later versions will work. I do know that the last Classic-capable version of Intech SpeedTools will not work (I tried and it actually nuked the A/UX slices! don't use it!), and I am told that FWB Hard Disk Toolkit should work, but I don't know which version. My Quadra 800 uses Silverlining on an 18GB Seagate Barracuda.

Silverlining should be able to take over the driver partition and move things around appropriately, but I'd simply format the drive from scratch. Use HD SC Setup 7.3.5 (the patched version above) to remove all existing partitions, then run Silverlining itself to create the new partitions. You can boot from some Silverlining CDs, but I booted from a 7.6 second SCSI volume for this purpose. Hint: Silverlining's input methods are a bit wonky, so be methodical. Select Partition Type from the pull-down menus with the cursor in the size column first, then enter the size, then the volume name, as appropriate. On my 18GB Barracuda, I used this scheme:

You will notice that Silverlining will see that we have two A/UX slices (not counting swap). It will give you two commands. Write these commands down: you need the device string (something like /dev/rdsk/c2d0s0) for each command for the next set of steps.

Thus endeth the Partitioning. Now boot off your A/UX boot floppy and CD. Follow these steps carefully!

First boot

Once finished, you will be instructed to reboot. When you reboot and the MacPartition starts up and tries to initialise A/UX, it may fail resoundingly (unless you used the Easy Install approach, which works around this problem). Don't be discouraged. This failure is because the Launcher's standalone copy of fsck looks for an Autorecovery partition, which we have gloriously eschewed. Go to Settings, Booting. Pick "custom command" and change the fsck command to cat /etc/motd.

While you're at it, whether it boots or not, consider changing the launch command to launch -v so you have a better idea what's going on. Save the settings. (In future, you can always interrupt a boot by pressing Command-Period (Cmd-.) when the splash screen comes up.)

Boot with Command-B. This first boot will rebuild the kernel according to your system devices. Get a cup of coffee, preferably from Colombia, because on my IIci this took a good few minutes. You will then be instructed (forced) to reboot.


Welcome to A/UX. If you did it right, on the next boot, the system will come up, start A/UX (and you'll see the kernel coming up), and then drop you into ... the Finder? However, if you go under the applications menu on the top right, you'll see the Command Shell. Select that, et voila -- a real shell in your real A/UX system.

At this point, you're on your own. Things to do might include:

Remember to shut down the usual way, i.e., Special, Shut Down. You can also log out under the Special menu as well. When you do shut down or reboot, don't forget to unlock your MacOS partition next time you have HDSC Setup handy if you locked it with the steps above.

Things To Remember

Although there is a MacTCP control panel, you can't use it to change your network settings, and there is no DHCP client support. Network settings are managed The Unix Way, which is to say, ifconfig and the like. They will then show up in MacTCP. For that matter, change your DNS settings in /etc/resolv.conf (create it if it does not exist).

The Startup Disk control panel in A/UX and the MacPartition is absolutely useless on multi-partite disks of large size. The control panel from 7.6.1 is a better choice and will work just fine. Remember to keep your old one just in case, and leave the Startup Disk window open as you select restart or shut down. Note that this means you will need to reboot and stop the A/UX boot with Cmd-Period to run the 7.6.1 Startup Disk control panel from the MacPartition; it will crash the A/UX Finder instance if you run it there.

If you have a Power Macintosh card in your system, you must turn it off before booting from the MacPartition into A/UX. You can still have it plugged in the PDS slot, but it must not be activated (you can tell which one is running from the startup chime -- either the musical sting (68040) or the ominous strings (601)). If you don't do this, you may need to boot from a floppy or CD to get your startup disk switched to something else.

Things Not To Do

None of these apply to your MacOS partition (but this DOES apply to the MacPartition as well as the ute-and-root partition), which we created to allow you to have some partition on the system for these things.


This document is perpetually under construction. Have fun!
Cameron Kaiser