HP 48g Graphing Calculator - Manual (Page 59)

5
Hemon
The HP 48 has two types of memory:
m Read-only memory (ROM). ROM is memory that’s dedicated to
specific operations and cannot be altered. The HP 48 has 512 KB
(kilobytes) of built-in ROM, which contains its command set.
Except for the HP 48G model, you can expand your calculator’s
ROM by installing plug-in application cards (described in chapter
28).
■ Random-access memory (RAM). RAM is memory that you can
modify. You can store data into RAM, modify its contents, and
purge it. Except for the HP 48G model, you can increase your
calculator’s RAM by adding memory cards (described in chapter
28).
RAM is also called vser memory because it’s memory that you (the
user) have access to. You use or manipulate user memory when you
enter an object on the stack, save an object in a variable, delete
a variable, create an equation or matrix, run a program, etc. In
addition, the HP 48 periodically performs a system cleanup to free
memory for use.
The figure on the next page illustrates how the built-in RAM in the
HP 48 is organized. Note that the figure is not to scale.
Memory 5-1