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Chapter 5

RAMEXPAND

RAMEXPAND is a software package consisting of a set of

functions for extending the amount of RAM available to Applesoft

and Integer programs. RAMEXPAND will use the memory on one or

more Saturn 32K, 64K or 128K RAM Boards as well as that on any

16K board present in the system. Information in the form of data

and programs or subroutines can be saved on these extension RAM

boards for later retrieval. RAMEXPAND allows one to save

complete programs which can later be loaded and run, overlay and

chain subroutines and program segments, or save and recall arrays.

Flexibility has been incorporated into RAMEXPAND to allow

portions of the memory board(s) (Saturn 32K, 64K, 128K RAM

Boards, 16K board) to be reserved for such things as the

alternate BASIC (Applesoft in Apple II, Integer in Apple II

Plus). This memory can be reclaimed for use by RAMEXPAND at any

time it is desired.

I. CHARACTERISTICS OF RAMEXPAND

A. TERMINOLOGY

Throughout this chapter, the term “extended RAM” will be

used to describe the total memory present in the system contained

on expansion RAM boards (Saturn 32K, 64K, 128K RAM Board(s), 16K

expansion RAM board(s)). It should be noted that it is NOT

necessary to have a 16K RAM board for any of the software

provided by Saturn Systems; however, our software will take

advantage of any 16K card which you may have purchased prior to

the introduction of the Saturn RAM Board(s).

B. REQUIREMENTS AND MEMORY USAGE

RAMEXPAND occupies two portions of memory. Most of the

RAMEXPAND system is located in the Saturn 32K, 64K, or 128K board

which contains the relocated DOS and occupies the unused 4K bank

within the second 16K bank of the board (bank which contains the

relocated DOS). This is 4K bank 2B (see Technical Information

section, Chapter 9). One page of memory from $BDOO to $BDFF (just

below the interface routines to the relocated DOS) is also used

by RAMEXPAND and HIMEM is set to protect this portion.

The RAMEXPAND system consists of three files, RAMEXPAND,

RAMEXPAND.LOW, and RAMEXPA.LOAD. The program RAMEXPA.LOAD serves

to load the RAMEXPAND system into memory and set various poin—

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Apple Logic Board Technical Information Seite 26