When the G4 Cube was introduced in 2000, Apple released it with either a 20GB or a 30 GB hard drive. Consistent with these sizes, the machine’s ROM generously supported booting from up to 128GB of disk – plenty for the time. Since then however, the machine has become a cult favourite and is often heavily upgraded. Cubes are frequently seen on eBay with 160GB hard drives, and I recently saw one with a 750GB hard drive! Given the 128 GB hard drive limitation, what is going on here?

The quick answer is that the 128GB barrier is a firmware limitation, and so as long as the operating systems you wish to boot reside completely below the 128GB line, you can boot them successfully. In my case, with a roomy 320GB hard drive freshly installed into my Cube, I chose to install all of Mac OS 9.2.2, Mac OS X 10.4.11 and Mac OS X 10.5.8.

Respecting the “all boot partitions below 128GB” rule, I partitioned the first 128 GB into three boot partitions of 14GB, 24GB and 24GB (for Mac OS 9.2.2, Mac OS X 10.4.11 and Mac OS X 10.5.8 respectively), plus one 68GB data partition. That left something less than 192 GB of available disk space that none of the OS on the Cube could “see”. Therein lies the challenge – how can a Cube OS be equipped such that it CAN see all of this extra space? The answers vary by OS and by your pocketbook. Lets look at each one of the OS I equipped on my Cube.

Mac OS 9.2.2: Mac OS 9.2.2 is an amazingly productive environment and feels crisp and responsive on my Cube. If only there were a modern web browser for it… sigh. Classilla is good, but not good enough. Anyway, I digress. You would think that something as old as Mac OS 9.2.2 would be a lost cause for seeing above the 128GB barrier, but this was not the case, and the fix was amazingly simple. Advised by the very helpful denizens of the forums at http://www.cubeowner.com, I hunted through my Cube’s Mac OS 9.2.2 System Folder, and replaced the “Mac OS ROM” file there with the newer one from the System Folder of the Classic installation on my PowerMac G5 running Mac OS X 10.4.11. With the newer “Mac OS ROM” file in place in my Cube’s Mac OS 9.2.2 System Folder, I restarted and was immediately able to “see” and use the entire 320GB of the hard drive. This is actually pretty interesting, given that my Classic installation was for a G5, and I was now dumping a file from it into the System Folder of a G4 machine, but happily it all worked! Of course, if you don’t have a PowerMac G5 Classic install to pull from, this solution becomes a bit problematic, but if this is the case, please leave me a message and I can make the right file available for you.

Mac OS X 10.4.11 (Tiger): To this day, Mac OS X Tiger is my favourite OS X release of all time. It is simply beautiful to look at, bright and colourful, and there is almost nothing it cannot do. As I have posted previously, new and very capable web browsers and email clients exist for it, and I even managed to get the majority of my iTunes library imported into Tiger’s iTunes. It is a marvelous and very productive environment. Alas, it could not see across the 128GB divide on my Cube. Now for a bit of serendipity. Back in 2006 when I got my first Mac, a PowerMac G5 Dual 2.3 GHz, I bought Intech Disk SpeedTools for it, so I just happened to have their ATA Hi-Cap Driver, and their ATA Drive Extender program available at hand. I installed the Hi-Cap driver into Tiger and restarted, and it was then able to see the full 320 GB of the drive. I followed this up with use of the Intech ATA Drive Extender, to modify the partition table and add one final partition that covered the remainder of the disk. This went from the 128 GB line to the end of the disk (in this case about 170 GB) and after a restart, was fully visible and useful from Tiger.

So what do you do if you do not have Intech SpeedTools available? Well happily, even after all this time, you can still buy them! Visit http://http://www.speedtools2.com/shop.html if you are interested. At about $US 60, they ARE a bit “dear”, and this was the basis of my “vary by pocketbook” comment above, but they are still very good. For the record, I am not associated with Intech in any way – just a satisfied customer.

There is reportedly a free alternative, which I tried but was not able to get to work. Visit http://http://4thcode.blogspot.fr/2007/12/using-128-gib-or-larger-ata-hard-drives.html for all the details. It involves manually inserting a small script into the OS X startup routine. While it sounded simple, I was not successful with it, and so I moved on to the SpeedTools solution, since I had it available.

Mac OS X 10.5.8 (Leopard): No need to belabour this one. The story here is identical to 104.11 EXCEPT that there is a separate, Leopard-specific version of the Intech Hi-Cap driver. Be sure to use that one, and not the Tiger version, which did not work at all with Leopard (I tried it!).

So there you go – hard drives of pretty much any size you might wish on your G4 Cube!