Compaq 1610 Reference Manual page 69

The handheld PC stores your personal information (data you have
entered and third-party applications you have installed) in the
device's RAM (random access memory). However, a power loss
or other disruption of power can cause your data to be deleted
from the handheld PC.
Your C-Series provides you with several ways to protect against
this kind of data loss. You can:
back up data to the computer
back up data to an ATA Flash RAM PC Card
back up data to flash memory located in your C-Series. (Flash
memory is an area in your device that securely stores saved
information even if there is a power loss.)