Generally it's best to leave these features enabled. If very little mem-
ory is available and large objects have been saved by the recovery
features, you can safely regain some memory by disabling and re-en-
abling each feature, thereby clearing the stored objects.
The HP-28S contains 32 Kbytes of user memory, of which about 400
bytes are reserved for system use. Virtually every HP-28S operation
requires some memory use-even interpreting the command line. The
amount of memory used by some algebra commands (COLCT,
EXPAN, TAYLR) increases rapidly as their arguments become more
complicated. Try to leave at least a few thousand bytes of memory
free for dynamic system use.
You can check the amount of available memory by executing MEM,
found in the MEMORY menu.
Because the HP-28S operating system shares memory with user ob-
jects, you can fill memory so full of user objects that normal calculator
operation becomes difficult or impossible. The HP-28S provides a se-
ries of low memory warnings and responses, listed below in order of
Insufficient Memory. If there isn't enough memory available for a
command to execute, an
f fie i
error occurs. If
LAST is enabled, the original arguments are restored to the stack. If
LAST is disabled, the arguments are lost.
No Room for UNDO. If there isn't enough memory available to save
a copy of the stack, a
m for UNDO
error occurs. The UNDO
feature is automatically disabled; to reenable UNDO, press
the MODE menu.
No Room to ENTER. If there isn't enough memory available to pro-
cess the command line, the calculator clears the command line and
A copy of the unsuccessful com-
mand line is saved in the command stack if the command stack is