Sony PCG-505GX - Manual (Page 18)

VAIO MicroNotebook Computer User Guide
Ergonomic Considerations
You will be using your notebook computer as a portable device in a
variety of environments. Whenever possible, you should attempt to
apply the following ergonomic considerations to both stationary and
portable environments.
Computer positioned
directly in front of you
Position of your computer - Place the computer directly in front of
you as you work. Keep your forearms horizontal, with your wrists in
a neutral, comfortable position while using the keyboard, touchpad,
or external mouse. Let your upper arms hang naturally at your sides.
Take breaks during sessions with your computer. Excessive use of the
computer may strain muscles or tendons.