Variables and memory management 14-1
14
Variables and memory management
Introduction
The HP 39gs has approximately 200K of user memory. 
The calculator uses this memory to store variables, 
perform computations, and store history. 
A variable is an object that you create in memory to hold 
data. The hp 39gs has two types of variables, home 
variables and aplet variables.
• Home variables are available in all aplets. For 
example, you can store real numbers in variables A 
to Z and complex numbers in variables Z0 to Z9. 
These can be numbers you have entered, or the 
results of calculations. These variables are available 
within all aplets and within any programs.
• Aplet variables apply only to a single aplet. Aplets 
have specific variables allocated to them which vary 
from aplet to aplet. 
You use the calculator’s memory to store the following 
objects:
• copies of aplets with specific configurations
• new aplets that you download
• aplet variables 
• home variables
• variables created through a catalog or editor, for 
example a matrix or a text note
• programs that you create.
You can use the Memory Manager (  
MEMORY) to 
view the amount of memory available. The catalog views, 
which are accessible via the Memory Manager, can be 
used to transfer variables such as lists or matrices 
between calculators. 
HP 39gs English.book  Page 1  Wednesday, December 7, 2005  11:24 PM