A/UX was designed for the legacy Macintosh (those based on the Motorola 680x0 line of processors), and was never ported to the PowerPC. If you're trying to install on a PowerPC, stop now... It will not work. Similarly, none of the PowerBooks, LC's, or AV Macs are supported. A/UX bypasses the Macintosh Toolbox, and communicates directly with the hardware, so changing the gestalt (system ID code) will not let you install on an unsupported model. Unfortunately, this also rules out any of the current Macintosh emulators. None of them reproduce the CPU, PMMU, FPU, and SWIM chips well enough to fool A/UX.

The chart below shows all fifteen supported Macintosh models, and what versions of A/UX they will run. Note that A/UX requires a PMMU (Programmed Memory Management Unit) and an FPU (Floating Point Unit). The PMMU is integrated in all but the original Mac II. The Centris 610/650, and some low-end Quadra 610's shipped with a 68LC040 processor (no FPU). Before installing on one of these models, you will need to replace the LC040 with a full 68040 processor.

Also note that A/UX will not run on the LC series, with or without a full 68040 processor - The video subsystem of the LC's is not supported by A/UX. A considerable amount of work (and access to the A/UX source code) would be required to make it compatible. So grab a Quadra (or a Centris) while you still can!

Note: While the Mac II, IIx, IIcx, IIci, IIsi, and the SE/30, will run A/UX 3.1.1, performance will be less than spectacular. The "wicked fast" Mac IIfx would probably be okay, but I would recommend a 68040-based Mac for A/UX 3.1.1

A complete installation of A/UX 3.0.1 will require about 80MB of hard drive space (160MB recommended), and 8MB of RAM (16MB recommended). Apple Support Doc ID9129 I have a Quadra 610 that runs quite nicely with an 810MB hard drive and 16MB of RAM, and a Quadra 800 that smokes with 2GB and 64MB. Try to keep your specs within reason though:

Just because it's got an Apple logo on it doesn't mean it's going to work... A/UX is rather particular about the cd-rom drive. The comp.unix.aux FAQ lists the following drives as 100% compatible: AppleCD SC, CD-150, CD-300, Toshiba XM3201, XM3301B, XM3401, XM3501, DEC RRD42, RRD40 (LMSI CM-212), Sun CDROM (Sony CDU-8012?), CD-Technologies Porta-Drive, Chinon CDA-431, Denon DRD 253. The faq also states that A/UX 3.1 adds support for NEC cd-rom drives... Unfortunately, it doesn't specify which models.

Personally, I've used the AppleCD 300 Plus (Sony CDU561-25), AppleCD 300i Plus (Panasonic/Matsushita CR-503-K), AppleCD 600i (Panasonic/Matsushita CR-504-C), and the Toshiba XM6201B to install A/UX. Others have reported success with the Apple 12X (Panasonic/Matsushita CR-507-C). I suspect the operating system needs a cd-rom drive with a 512 byte sector size (many newer drives use a sector size of 2048 bytes) or a drive that responds to the "MODE SELECT" command. If you successfully install A/UX using an "unsupported" drive, please email the make/model to me or the maintainer of the new A/UX faq.

The comp.unix.aux FAQ lists the Apple EtherNet card, 3Com EtherLink NB, Asante MacCon, and StarNet cards as compatible. Others might work, but your safest option is to choose a Macintosh with onboard ethernet like one of the Quadras. Personally, I have used the MacCon MC3NB under A/UX versions 2.0 and 3.X with success. As with the cd-rom drive, if you get an unsupported network card to work, please let me know!