A Mac Plus as set up in a Spanish computer museum.

The MiSTer features the so-called macplus core, which emulates a Macintosh Plus computer which was originally released in 1986 for the princely sum of $2.599. In today’s money that would come down to a little over $6000 for a relatively tiny machine with a Motorola 68000 CPU running at 8MHz., 1MB of memory, a monochrome display and a floppy drive integrated in Apple’s signature beige box. Yes, this is indeed a very retro Macintosh and you’ll be very hard-pressed to find any legitimate use for it other than historic interest.

One of the reasons for that is because the Mac is still a current platform and has kept on evolving, giving you much more productive options to emulate by other means than the lowly Mac Plus on the MiSTer. Look towards Basilisk II on your contemporary system if you want to run a 68K Mac application comfortably. It will give you higher screen resolutions, colour displays and the means to run Mac OS up to 8.1 which is a huge improvement over the System 6 you get on the FPGA Mac Plus.

Only one button

Apple long held the firm belief that computer mice should really only have one button. Many pundits derided them for this over the years, but this quirky conviction betrays a very sane principle. Macintosh computers, especially the older generation like the Plus, were built to “Just Work”. Yes, capitalized because it was an actual marketing slogan of the company at some point in time.

It means that, unlike the IBM PC or the many 8-bit microcomputers that surrounded it at the time, the Macintosh had no command line interface. It wasn’t even optional, like it was on the Amiga. Everything is controlled through a very distinctive graphical interface which was revolutionary for its time. It had clean and crisp black and white lines which made the system an almost ideal choice for those in the business of print publishing. Paired with the LaserWriter printers which sported full-on PostScript printing, the Macintosh and the publishing industry were an instant hit.

As a European I only ever saw a single Macintosh computer in a private home at this point in time. They were prohibitively expensive. And by prohibitively I mean that you could get almost four fully decked-out Amiga 500 systems for the price of a single Macintosh Plus.

So where does my Mac nostalgia come from? School! I studied Journalism in the late 90’s and the building there was packed with Apple computers. Everything from the lowly Plus all the way up to mouth-watering blue PowerMac G3’s were strewn around the building. I was a complete Windows aficionado at the time but quickly became enamored by the rigorously executed simplicity of the Macintosh. It really just worked!

On to the MiSTer

Sadly, though, getting a Mac Plus on the MiSTer is hardly a walk in the park. The first thing you’ll need is a boot ROM to go with your macplus core. There’s a suitable 128KB ROM file available from the macplus core’s Github repository. But that’s not all you’re going to need.

When you set the core up with the ROM and first fire up the system, you’ll be greeted by a stippled screen with an icon of a floppy disk in the center. This is Macintosh' way of requesting a bootable floppy image from you.

The Mac Plus comes from an era when hard drives were very much optional and considered a luxury item for all but the more expensive business computers. The idea with the Mac Plus was for the user to plop a disk into the machine’s single floppy drive, and that would then boot a complete instance of the operating system for use as the foundation for the application or game that would also be on the disk. Inefficient? Yes, quite, but it’s what we had at the time. The nearest contender, the Amiga, was hardly any different.

Creating a hard disk

The good thing about working with the MiSTer is that we do have the luxury of adding a hard drive. You can keep these very small, relative to modern sizes. My emulated Mac Plus has a 20MB hard drive and I still have room to spare. You can create the hard drive image very simply from the MiSTer’s Linux environment by using the following commands, assuming your Mac Plus files live in /media/fat/macplus:

dd if=/dev/zero of=/media/fat/macplus/machd.vhd bs=1M count=20

This gives you a file of 20MB in size, filled with nothing but the number 0. Mount it on the Mac Plus as if it were a hard drive. Of course it won’t do anything yet, but at least the system will know that there’s a 20MB hard disk fresh from the shop attached to it.

Next step is to initialize your new hard disk. This is done using the HD Setup Tool which can be found on one of the floppies that make up the System 6 operating system distribution. Yes, you’ll need to hunt down a set of floppy image for Apple System 6 which each must be 800KB in size and not a single byte over or under. Yes, annoying. Drop me a line if you can’t find anything.

Once the disk is initialized and you gave it a name, you can run the installer script from the floppy and the system will take things from there. Be prepared for a bit of classical floppy-juggling as you progress through the installation. When it’s done, you’ll be able to eject the floppies and reboot your MiSTer as if it were a real Macintosh Plus from yesteryear.