Epson 10020 - Manual (Page 50)

If you have an optional 720KB drive, use 3 l/2-inch, double-
sided, double-density, 135 TPI, 720KB diskettes with this drive.
These diskettes contain 80 tracks per side, 9 sectors per track,
and hold up to 720KB of information-approximately 300
pages of text.
Note
You cannot use 3 1/2-inch diskettes that have been
formed for 1.44MB in a 720KB diskette drive.
You need to format new diskettes before you can use them with
MS-DOS. The process of formatting erases all data on a
diskette and prepares it to receive new data; so be sure to
format only new, blank diskettes or diskettes that contain data
you want to erase. See Chapter 3 for instructions on formatting
diskettes.
Caring for Diskettes and Diskette Drives
Follow these basic precautions to protect your diskettes and
avoid losing data:
Do not remove a diskette from the diskette drive or turn off
the computer while the drive light is on. This light
indicates that the computer is copying data to or from a
diskette. If you interrupt this process, you can destroy data.
Remove all diskettes before you turn off the computer.
Keep diskettes away from dust and dirt. Small particles can
scratch the magnetic surface and destroy data. Dust can
also ruin the read/write heads in a diskette drive.
Never wipe, brush, or try to clean diskettes in any way.
Keep diskettes in a moderate environment. They work best
at normal room temperature and in normal humidity. Don’t
leave your diskettes sitting in the sun, or in extreme cold or
heat.
Using Your Computer 2-9