In which I am thoroughly a geek.

This post is about how to run Mac OS9 on an Intel Mac. If that sentence didn't interest you, I can't advise you strongly enough not to read the rest. Really, life's too short. Go play tennis.

But maybe you're as much of a geek as I am and want to find out how to do this. Maybe, like me, you've been looking for instructions for this for days and have found a fragment here, a fragment there, but nowhere a simple list of start-to-finish instructions. Well, here they are. Plus some rambling, but hey.

First off, you might well ask why, when OSX is probably the best operating system ever, I would want to run OS9, which, for all its good points, wasn't. Well, there is a rather nice granular synthesis application called thOnk. It's a tiny little app by audio standards — about half a meg — but it is utterly brilliant. And its makers have no intention whatsoever of ever recoding it for OSX. Shame. There are other granular synthesis programs out there, and they're pish. None of them come even remotely close to thOnk.

So my ongoing project to rebuild me recording studio is, well, going on, and it dawned on me that I've got a bloody great G3 iMac — they're the original ones that look like the front of an aeroplane but weigh a little more — taking up a huge amount of useful and valuable space just so I can run this one tiny app. Surely, I think to myself, there must be some way of running it on me new MacBook and getting that great lump of a spare computer off me desk. Apple switched to Intel chips a few years ago now. Someone must have come up with an OS9 emulator.

And a handful of people have. There's something called OS9exec, which, as far as I can tell, is probably brilliantly expertly programmed and probably works, but can only be installed by unbelievably clever people who can sing four-part harmonies in Unix, and there's another one called, fantastically, SheepShaver, which has virtually no documentation at all. I tried both, and have finally, after much struggle, got SheepShaver working.

And it's brilliant, it really is. It runs OS9 pretty much perfectly in its own window in OSX. I love it.

It's actually quite simple to install, once you know how. There are three complications. Firstly, like I said, there's sod all documentation. You have to spend hours with Google, tracking down the various conversations users have had about it, picking out useful bits and trying things that might work. And all these users are dead knowledgable about Mac operating systems and assume quite a bit of expertise on everyone else's part. It's hell. Secondly, although Apple have fully abandoned OS9 and have no intention of ever having anything to do with it ever again, they still haven't (unlike OS7 and OS8) made it a free download. In fact, they still assert their copyright over it and crack down on anyone who does make it — or crucial bits of it — available. So no-one can put together a simple click-here-to-install all-in-one SheepShaver package that just works. Installing it simply cannot be user-friendly, for legal reasons. Tsk. That's alright, you might be thinking; I have an OS9 disk. Well, thirdly, SheepShaver requires a retail copy of OS9 — not a machine-specific install disk, which is almost certainly what you have. It's what I have. This was a real sticking point until I stumbled across some genius called EVWeb who's figured out how to install from a machine-specific restore disk. If you've got an install disk, you've probably got a restore disk too. I have. Happy days.

Oh, by the way, SheepShaver only supports up to OS 9.04. 9.1 and 9.2 won't work.

So, here we go. I wasn't taking notes as I went, so some bits might be slightly vague. Not all Macs and Apple disks are the same, of course, so some of the filenames might be slightly different for you in places, but they should be similar. Just use your common sense. Oh, and one thing I've definitely discovered over the last few days is that what works on one person's system may not work on another's, so this might not work for you, in which case my apologies. But I'm still confident that these instructions are better than any others I could find out there. I hope they're easy enough for laymen to follow.

First, download SheepShaver. When you uncompress the package, you'll get a folder called "SheepShaver-2.3". Put the whole folder in your Applications folder or your Utilities folder. Or wherever you like, I suppose, but it is an application, after all.

Now, you need to get hold of an old Mac ROM. SheepShaver will not work without it, but doesn't come with one because this is one of those bits that Apple won't let anyone else supply. So you need to get it yourself. First, download it from Apple's site here. There are a lot of ROMs around, but quite a few people claim that that one is the only one that will allow SheepShaver to work. Secondly, download TomeViewer. TomeViewer will allow you to extract the single ROM file that you need from the ROM update file that you've downloaded from Apple. It's pretty straightforward, but there's a catch: it's an OS9 app, so you need access to a machine already running OS9 in order to use it. This is a total pain, obviously, but I've been unable to find any way around it: before you can run this OS9 emulator, you need to be able to use OS9. Or get the ROM file from elsewhere, illegally.

Anyway, once you've done this stuff with TomeViewer, you should have a file called "Mac_OS_ROM". Place it in your SheepShaver folder.

Now you need to create a folder for transferring files — including applications that you wish to install — between OSX and OS9. So start up Disk Utility — it's in your Utilities folder. Click "New Image". Call this disk image "FileTransfer" and place it wherever you like — in your Documents folder makes sense. Choose the size you need — if in doubt, just go for 500MB. Memory's cheap. Encryption: none. Format: read/write disk image. Click "Create".

When Disk Utility has finished creating this disk image, it will mount it on the desktop for you. Make sure you eject it before attempting to run SheepShaver. You must never have SheepShaver and OSX trying to access the same disk image at the same time. It could screw up your system, apparently.

Now you can actually start SheepShaver.

Double-click the "SheepShaverGUI.app" icon. This is simply a graphical interface for SheepShaver's settings. It's pretty easy to use.

Click on the "Memory/Misc" tab. Type in your preferred RAM size — I used 256. Then click on the "Browse" button and locate your ROM file. "Don't Use CPU When Idle" should be ticked; "Ignore Illegal Memory Accesses" shouldn't.

Click on the "Volumes" tab. Click "Create". This is where you create your OS9 volume — the virtual disk that SheepShaver will treat as OS9's hard drive. Navigate to your SheepShaver folder, type "Mac_OS_Volume" under "Selection", choose a size for your volume — 250MB is big enough for the basic operating system; use more if you're planning to install lots of applications in OS9 (though don't worry if there's not enough room to install them, as you can simply create more of these virtual volumes later) — and click "OK". Wait a little while while SheepShaver constructs the virtual disk.

Now click "Add". Navigate to the "FileTransfer.dmg" file you created with Disk Utility and select it. You should now have two volumes in your list.

Leave "Boot From" as "Any".

The other tabs in SheepShaverGUI are optional. You can set the size of the window OS9 will appear in under "Graphics/Sound". I've seen some people say that trying to use "Fullscreen" mode crashes their systems; others can use it no problem. I've seen it recommended that the window refresh rate be set as low as possible, and mine is set to 60Hz.

Under the "Keyboard/Mouse" tab, you can set what your mouse's scrollwheel should be doing. OS9 doesn't support scrollwheels naturally, apparently, so SheepShaver uses your settings here to trick OS9 into supporting them. Cool.

Apparently, you should enter "slirp" under "Ethernet Interface" on the "Serial/Network" tab. I have no intention of using networky stuff in my OS9, so can't confirm whether this works. Sorry.

Now put your OS9 disk into the drive and click SheepShaver's "Start" button.

OS9 will want to format what it thinks is its hard drive: the "Mac_OS_Volume" virtual drive you just created using SheepShaverGUI. It will ask if you want to format the drive and warn you that doing so will delete everything on it. The reason you can be sure that this is safe and not about to destroy your system is that it tells you the drive's size, and it's exactly the same as the size you typed in when creating the virtual drive — in my case, 250MB. Go ahead and format it. You have a choice between Standard and Extended format. I believe Extended should work, but I used Standard.

Once the virtual drive is formatted, SheepShaver will boot OS9 from whichever disk you've put in the drive. If your disk is a retail non-machine-specific OS9 install disk, the rest should be easy. Just install as normal, you lucky sod.

If it's a machine-specific install disk, there are instructions here which I have not attempted to follow. Good luck if you do.

If it's a machine-specific restore disk, have a look inside it and open the folder called "Configurations". In there is a disk image — on my disk, it's called "iMac HD.img". Open it. Now drag its contents into your "Mac_OS_Volume" virtual hard drive, which you will see appears on the desktop like a normal hard drive. You don't really need to copy all these files. I just copied the System Folder and the "Apple Extras" folder; I'm pretty sure that only the System Folder is really necessary. Pick and choose whichever bits you want. If in doubt, just copy the whole lot.

When the system's finished copying all these files, open the "Startup Disk" control panel. Select "Mac_OS_Volume" and click "Restart".

Assuming all that worked, from now on, you will not need to use SheepShaverGUI. Just double-click on SheepShaver.app to run OS9.

By the way, that "FileTransfer" disk image will also appear on the OS9 desktop like a hard drive. Use it to transfer files between the two operating systems. In OSX, open the disk image and place your files into it. Then start SheepShaver, and when OS9 has booted up you'll be able to access those files in the "FileTransfer" hard drive on the desktop. But do remember never to open the disk image in OSX while OS9 is running.

That's it. Have fun.

If you have any questions, I'll probably be no good at answering them. But I'll try.