When you get a vintage Macintosh, the first thing you’ll need to do with get it to boot up. It is hard to install software, upgrade hardware or add accessories if the thing won’t actually run :-). That means getting a version of Mac OS (“the System”) up and running. This piece focuses on older Macs that support SCSI hard disks, since those are little more complicated.
The First Time
If you’ve done things right, your hard drive-based vintage Macintosh already has a version of the System installed. A few eBay vendors and refurbished Mac retailers ensure that their machines have the appropriate version of the system installed. Sometimes, though, you want to add a hard drive to a floppy-only Macintosh Plus or first-generation Macintosh SE. You may have obtained a machine where you’ve had to replace a dead hard disk, or where the disk is wiped with nothing on it. That means you need to be able to format the drive and install a copy of the operating system.
You can get System installation disks on either floppy or CD. You may be able to create a set of installation floppies from a CD, if you have the appropriate hardware. Which path you have to take will depend on what you have now, and what you have available.
Starting From Floppies
If you don’t have the system installation on a CD, have no way of making a CD, or have no way of reading a CD with your vintage Macintosh, then you have only one choice: get a copy of the System installation on floppies. There are usually some available via places like eBay. All floppy-enabled Macintoshes can boot from floppy disk.
However, if you want to use a SCSI hard drive, you do have to get a version of the System installation that includes the Apple HD SC Setup application. On a standard installation set, this is usually found on the Disk Tools (or Disk Tools 1) diskette. Finding these for System 7 and newer is usually pretty easy. Finding something for System 6 and older is a bit more challenging ever since Apple shut down their servers for vintage Macintosh software.
A quick word on floppies: remember that not all Macintoshes supported all 3 floppy formats. The original 128k and 512k Macintoshes only supported 400k (SSDD) floppy disks. The Macintosh Plus, Macintosh SE and first Macintosh II supported 400k and 800k (DSDD) floppies. Starting with the Macintosh SE/30 and onward, 1.44MB (HD) disks became the norm. Getting a set of System 7 disks on 1.44MB HD disks doesn’t do you any good if you have a Macintosh Plus.
Starting From CD
If your vintage Macintosh has a CD-ROM, and you have a System installation CD, then you might be able to install directly from the CD. But a word of warning: not all CD images can be booted from directly. I have a set (from System 7 through to System 8) that I created from disk images obtained on-line, and they install just fine. But I cannot get my Macintosh Plus, SE/30 or Portable to boot from the CD image. Your mileage may vary. If you can’t boot from the install CD, then you are left with the aforementioned “Starting From Floppies”.
If you do have a CD image and a running machine that can read them, I strongly recommend that you use the diskette images on the CD to make a diskette installation set. At a minimum, make the Disk Tools set, because you can always boot from those to perform any hard drive repair or re-install the system from CD.
Backups and More Backups
You will want to make sure you make and keep backups for your vintage System installation floppies. Floppy diskettes can fail, and you don’t want to find out that your one and only copy of a system is no longer usable.
If you have your installation on CD, make a floppy set from the CD if the images are available. This is your backup, a way to ensure you can still boot your machine and install your system onto a new, unformatted hard drive. You can either install everything from floppies, or you can boot from one of the Disk Tools floppies to format the drive and access the installation on CD.
Hopefully you don’t have to install your operating system very often. But keep a good set of installation media available in the event you do.