Apple Macintosh PowerBook 1400 - Manual (Page 185)

What you need
Just as you need paper to make copies of important documents, you need
floppy disks to make copies of the information on your hard disk. You can
probably buy the floppy disks at the same place you bought your computer.
Floppy disks come in a variety of sizes and capacities. The ones you need for
backing up your hard disk are called high-density 3.5-inch disks. You can
recognize the disks by the way they look:
Even though these disks have a hard plastic casing, they are called “floppy
disks” because the disk inside the casing is floppy.
Before you start making your disks, you’ll need to decide if you want to make
a full set or a minimum set of disks. When you make a full set, you’ll make
disks for your system software and most of the other software that comes on
your computer. When you make a minimum set, you’ll make just the core
system software disks. It is best to make a full set, so you’ll have installer
disks for your system software and most of the other software that comes on
your computer. However, making a full set requires more disks and more time
than making a minimum set. At the very least, make a minimum set of disks
now. If you choose to make a minimum set, you can make disks for the other
software later.
If you don’t have disks on hand, you can skip these instructions for the
moment. But the sooner you make the system software disks, the better. Buy
the disks as soon as possible; then return to this section and follow these
instructions.
IMPORTANT Be sure you make at least a minimum set of disks as soon as
possible, in case you need to reinstall your system software.
High-density disks
have two holes...
...and they have
this symbol.
185 Making Backup Floppy Disks