Epson 10020 - Manual (Page 215)

2. Type the following and press Enter:
COPY CON AUTOEXEC.BAT
3. Type the following, pressing Enter after each line:
ECHO OFF
CLS
PROMPT = SPSG
PATH = C:\DOS
4. Then hold down the Ctrl key and press Z. Then press
Enter.
Booting From the Hard Disk
Now you can load MS-DOS from drive C on your hard disk. Be
sure there is no diskette in drive A when you turn on or reset
your computer. Otherwise, the computer tries to load MS-DOS
from the diskette in drive A. If drive A is empty (or the latch is
up), MS-DOS is booted from drive C.
F-8 Preparing a Hard Disk for Use