Texas Instruments TITANIUM TI-89 User Manual page 697

By creating additional folders, you can store independent sets of user-defined variables
(including user-defined functions). For example, you can create separate folders for
different TI-89 Titanium applications (Math, Text Editor, etc.) or classes. You can store a
user-defined variable in any existing folder.
The user-defined variables in one folder are independent of the variables in any other
folder. Therefore, folders can store separate sets of variables with the same names but
different values.
Name of current folder
You cannot create a folder within another folder.
Memory and Variable Management
MAIN
System variables
Variables
User-defined
a=1, b=2, c=3
f(x)=x³+x²+x
ALG102
User-defined
b=5, c=100
f(x)=sin(x)+cos(x)
DAVE
User-defined
a=3, b=1, c=2
f(x)=x²+6
MATH
User-defined
a=42, c=6
f(x)=3x²+4x+25
697