Your Mac Plus will run any system software, from the original System 0 through about System 7.5.5, though with 1 MB of RAM it can only systems up to 6.0.8. (System 7 was a big jump in terms of memory demands, needing better than 1 MB just for the system.) You can get a working boot disk with System 6.0.8 on it using just one 800K floppy, though of course it won't have all the frills available on a fixed disk (though you might be surprised what I've managed). The later the system, the better (and larger) it will be. While I started out using System 3.2, on a single 800K disk with Microsoft Word 1.5, I ended up using System 6.0.8. You get get disk images files of System 6.0.8 for free from Apple Computer; though you'll need an image-mounting program like [Mount Image, Shrink Wrap], and a Mac with a working system, to set up the disks. You can download the image files, mount them on an working Mac (i.e., trick the Mac into treating them like they're floppy disks, instead of the simple files they are), and make installation floppies for your Mac Plus. If you want older systems, you can download copies from the Mac 512K Pages (don't be a square: join the Mac512K user group, and help keep the SPA, and other cyber-Nazis, off our backs).

Now, System 6.0.8 is a strapping big piece of software; how can you fit it all on a single 800K disk? Well, you can't, of course, but you can get enough on a floppy to boot up a Mac Plus. The secret is to strip down the System file, using the Font/DA Mover. Do you really need all those fonts, and all those DA's (Key Caps, ScrapBook, etc.)? Use the Font/DA Mover to delete the stuff you don't want from the System file, and soon it'll be small enough to fit on an 800K disk with the Finder, and even some frivolous control panels, extensions, and what have you. Try it, you'll like it.

And if you only have one floppy drive, you better leave enough room on that boot floppy for your programs, or you're just gonna be looking at System 6.0.8. and nuthin else. UNLESS: you've got more than 1 MB of RAM to play with (i.e., 2.5 or 4 MB). In which case you can make a RAM Disk, which amounts to roping off a certain amount of memory, christening it "RAM Disk" (or "C" if you're really cool), and proceeding to treat it like the pseudo-hard disk that it is. All of which you can do with a little program called (fittingly enough) [RAM Disk]. Put it on the boot floppy along with a sufficiently stripped System 6.0.8, and you can even set it to kick out the floppy disk once it's set up the RAM Disk -- hence freeing up your floppy drive, hence enabling you to run an extra floppy's worth of programs, on top of the system. No need to thank me, I didn't write the program. [X] did, and RAM Disk is shareware.

Of course, since the price of hard disks is so low these days, you might as well just buy a SCSI hard disk if you really want to use your Mac Plus. But beware: according to some reports I've read, Mac Pluses are kind of finicky about which hard disks they'll work with. I got a used 80 MB external SCSI hard disks from MediaGuide and from Nexcomp that work just fine with my Mac Plus, and the nice thing is that if my Mac Plus croaks, the disk can always go on some other Mac. If you get an external hard disk, you'll need a SCSI cable (with a DB25 end to go into the Mac's SCSI port, and a Centronix 50 end to plug into the drive's "in" port), and also a SCSI terminator (a little plug that goes in the hard drive's "out" port, and ends the SCSI chain).