The Compact Mac Trio

I'll be right up front with my bias: I like System 7.5.5 and prefer to run it on Macs that don't support Mac OS 8.1 or later. That said, there are equally valid arguments for System 6.0.x and earlier versions of System 7.

System 7

I lean toward System 7 (7.5.5 in particular) primarily because it's familiar. I haven't done much with System 6.0.x since Apple released System 7.0. I like the way System 7 lets me change icons, supports submenus, better organizes items in the System Folder, simplifies adding and removing fonts, always lets you run as many programs as memory allows, supports aliases, and lets you share files on your hard drive over a network, although that feature does slow down these old 8 MHz computers.

In the final analysis, choosing System 7 is picking features and convenience over speed. An 8 MHz processor can actually feel fairly snappy under System 6, but will feel sluggish with System 7.

That said, System 7 requires a Mac with at least 2 MB of RAM and really wants to run from a hard drive. If you don't have a hard drive or have less than 2 MB of RAM, you'll want to upgrade your hardware or stick with System 6.

System 6

System 6 is sleek and fast. The whole operating system can run from a single floppy disk in about 300-400 KB of RAM, leaving plenty of room for most applications that run under System 6. Because it is so small, it also boots much more quickly than System 7.

Like System 7, it allows you to have more than one program active at a time. Unlike System 7, you can turn MultiFinder off under System 6.

Why Not Use Both?

Fortunately, you don't have to pick one or the other. There are several ways you can switch between System 6 and System 7.

1. Create a system floppy for your Mac for each OS. Switch operating systems by booting from the other boot disk.
2. Create a system floppy for the OS you seldom use. To boot that system, just insert the system disk at startup; your Mac will automatically boot from the floppy instead of the hard drive.
3. Use two hard drives, one for each OS - they're certainly cheap enough these days. Use the Startup Disk control panel to choose which system you'll boot from. (Exception: The Mac Plus loads the first system it finds in this order SCSI ID 6, 5, 4, 3, 2, 1, 0.)
4. Partition your hard drive and install each OS on a separate partition. Again, use the Startup Disk control panel to choose which partition to boot from. (Exception: The Mac Plus loads the first system on the partition that comes first alphabetically. In that case, make sure the partition you want to boot from come earlier in alphabetical order.)
5. Use System Picker.

System Picker

System picker is a freeware utility that lets you pick which one of two or more System Folders on your hard drive will be active at the next startup. Kevin Aitken's little utility does this by "blessing" the system you select. (Blessing is Apple's name for selecting one System Folder as the active one.)

You can download System Picker from Low End Mac's Dropbox account.

The trick you must master before using System Picker is installing two or more copies of the Mac OS on your hard drive. The first and most important thing to realize is that your System Folder doesn't have to be named "System Folder" - you could call one "System 6" and the other "System 7."

The second important thing to realize is that the Mac prefers to update an existing System Folder, so it will overwrite your other System if you're not careful. One way to work around this is to instruct the installer to perform a clean install, which renames the old folder Previous System Folder. This option is not readily accessible on older versions of the System, but if I recall correctly, you can access this option by holding down the option key while launching the installer.

Other ways to protect your old OS from the new installer are (1) to copy it to another drive or even a floppy disk, (2) rename the System Folder and compress it using StuffIt, and (3) rename the old System Folder and disable it by moving the System or Finder out of the old System Folder.

I have used System Picker successfully to choose among System 6.0.8, 7.5.5, and 7.0.x or 7.1 on my Mac II a few years back. Although it having multiple systems on a single hard drive is not recommended by Apple and can sometimes confuse the computer, I have never had any problems when using System Picker.

That's the quick system overview.

Other Links

• Why System 6 for compact Macs?, Manuel Mejia Jr, Mac Daniel
• Why System 6 for Mac IIs?, Manuel Mejia Jr, Mac Daniel
• System 6 Heaven
• System 6 Email List
• Jag's House