Re: Expanded memory in ProDOS

[supertimer@aol.com (Supertimer)]

tailkinker@home.com (Tail Kinker) wrote:

>Hi!  Can anyone send me some info on how to use the extended memory on
>an Apple 2e/c/GS?  I generally use ProDOS 8 and Basic, and have a meg
>of RAM just sitting there.

Which Apple II are you using?  First of all, using ProDOS 8
and BASIC.SYSTEM with Applesoft means you give up on
the IIGS' linear addressing of memory (up to 8MB of RAM).
Instead, the IIGS kicks into 8-bit mode and for all intents
and purposes, you have a computer that can access no
more than 64k since the IIGS is emulating a IIe!

So assuming this is really what you want to do, on the
IIGS, go into the control panel and set the RAM disk to
896k.  Reboot the IIGS into ProDOS 8 and BASIC.  Now
to see the memory, type "catalog s5,d1" and a RAM
disk pops up.

The simplest way to use the memory for BASIC is to
use it for page flipping.  Imagine an animation sequence
of hires graphics screens saved to the RAM disk as
FRAME1, FRAME2, FRAME3, etc.

A BASIC program can rapidly load the frames into
graphics memory resulting in animation:

10 HGR
20 LET X=1
30 ? CHR$(4);"BLOAD FRAME";X;",S5,D1,A$2000,L$2000"
40 LET X=X+1
50 GOTO 30

Of course you'd modify the program to stop at your
last frame otherwise it'll crash after the last frame.
You can in fact do this with double high resolution
too, but I don't remember the softswitches needed
to activate it.  Unfortunately, there's no way to do it
with Super High Resolution modes since the IIGS is
effectively a IIe under emulation mode.

With the IIe or IIc, you'd first need to set up the
RAM disk software.  For IIe Apple 1MB memory
card, this is automatic.  You'd then have to modify
the slot reference in line 30 of the above program to
the slot where the memory card resides (IIe) or is
mapped to (IIc).