Tandy 1000 Basic Reference Manual page 306

Chapter 10 I BASIC Ke.ywords
Erase
is an integer in the range 0 to 2 that tells BASIC how
much video memory to erase.
Erase
can be one of the following:
Do not erase video memory, even if the screen mode
changes.
Erase the union of the new page and old page if mode
or burst change.
Erase all video memory if mode or
burst
changes.
0
1
2
If you omit
erase,
BASIC assumes 1.
If you omit any parameters (except
display page),
BASIC uses
the previous values.
For more information on the graphics statements and video
pages, see CLEAR and Chapter 8, "Displaying Color and
Graphics."
Examples
1 0 SCREEN 0 , 0
selects text mode with color off.
6 0 SCREEN
2
changes to high resolution, 2-color, graphics mode.
304