power without the price
The ATARI ST emulator for Falcon 030
by Cyrille Dupuydauby.
adresse: 53 domaine des aigles
mailbox: Brasil, the ATARI BBS ou
Backward is Shareware, which means it is freely distributed (distribution will be
detailed later) so that anyone can use and judge it. If you find Backward useful and you
intend to use it on a regular basis, you must retribute its author, hence helping future
development. Backward III is the result of a (very) long work, please take this into
More precisely, Backward III is Keyware, which means the demo version (without
the registration key) is somewhat limited. Those limits do not prevent an intermitent
use, and whereas older version, no function is removed.
You'll find more explainations on registering further in this document.
Backward III may be distributed as long:
- the distributed is the demo (keyless) version.
- all files are kept unchanged (and please keep other languages files).
- the price for it just covers duplication and distribution costs.
-This document refers to standard actions such as using mouse, copying files,
formatting floppies and so on. In case of doubt, please refer to your computer
- This is the beta (pre-release) version of Backward III. It has been carefully
tested, and should be bug-free. The final release is due to July 1995, so please send
your comments or requests before the end of June.
Backward III (which will be now named as Backward) is an ST emulator, which
means it helps old ST software to work on your Falcon. Furthermore, Backward offers
some helpful functions, which easy the use of any software. Finally, Backward corrects
various system bugs, improving general performance.
Most of Falcon users knows Backward II and a few Backward I. But please take
the time to read this document, since Backward use as evolved.
Backward was created in April 1993 and is written in assembler.
Backward is a kit made of various files and programs:
- BACKLOAD.PRG and BCKWTSR.EXE files contain the emulator itself.
- BACKWARD.APP and the BCKW???.RSC files contain the library manager.
- PATCH.GTP, UNPATCH.GTP and the *.PTC files contain the patch programs
and patch scripts.
- MINIDESK.PRG is the desktop program used when the GEM is deactivated.
- BACKWARD.DKS contains the set-up library.
- BACKWARD.INF contains the preferences.
- the *.DOC directories contains this document in various languages and various
Even if Backward has been especially designed for hard disk, it can be used on a
floppy. Just take a DD (720Kb) floppy, create an AUTO directory and put
BACKLOAD.PRG in it. Then copy BCKWTSR.EXE, BACKWARD.* and the
BCKW???.RSC files on the root directory. You may copy the other files as you see fit.
Each time you'd like to use Backward, just start (cold start i.e power on) your computer
with this floppy in the drive. Backward will then install itself in memory. Once you're
back to the desktop, you can use any program. As long as you neither press the Reset
button neither do a cold start, Backward will be resident. So you don't have to keep the
- keeping the Alternate key down while booting prevents the hard drive to start
(you have to do it twice for booting on a floppy). Using this method you can put
Backward on a floppy if you do not want to have it always resident.
- keeping the Control key down while booting prevents AUTO programs and desk
accessories to be loaded. This way you can rename or delete BACKLOAD.PRG for
deactivating it (please remember that Backward is memory resident until the next cold
The hard disk installation is exactly the same than the floppy one. Just work on
drive C instead of Drive A. If you want to reduce boot time, install BACKLOAD.PRG
as the first program in your AUTO folder (for knowing the real file order, just use the
unsorted option). For altering this order, create on AUTA directory on drive C and
move the files from the AUTO directory to AUTA one by one. Then delete the
AUTO directory and rename AUTA to AUTO.
Anyway, BACKLOAD.PRG must be executed before MINT.PRG.
Sadly, it is impossible to use concurrently Backward and a virtual memory driver
(such as Outside or VRam).
When BACKLOAD.PRG is executed a message is shortly displayed. Then the
screen become a bit messy and your computer restart. If everything is ok, after the
ATARI logo is displayed, a message saying that Backward is resident is displayed.
If you have trouble in any of those stages, check that all files are presents.
You can also press one of the Shift keys when the message is displayed, it will
allows you do disable Backward (but it will stay in memory).
If you still have troubles, try booting with no desk accessories and no AUTO
programs (apart from BACKLOAD.PRG). If you have still problems, please contact
me (via internet e-mail if available).
As the emulator is memory resident, it is rather invisible. But once it is resident,
you can alter its set up through keyboard short cuts. Those short cuts are
Control+Alternate+ a numeric keypad key:
( for 16Mhz (high speed).
) for 8Mhz (low speed).
7 for deactivating the instruction cache.
8 for activating it.
4 for deactivating the data cache.
5 for activating it.
* for switching between PAL and NTSC display (50hz/60hz).
+ for louder sound.
- for softer sound.
Delete for doing a cold start.
Those short-cuts have been changed since Backward II (they look a bit more
logical now). You cannot alter the Blitter speed (it's useless). Those short cuts should
be always available, but sometimes the keyboard is deactivated (during floppy access or
after a crash).
Note for Backward II users: As you have certainly noticed, shot cuts have been
slightly changed. The Blitter frequency cannot be changed (it is kept at 16Mhz) because
it was useless.
The library Manager:
Preliminary note: The current version of the library manager is currently an
improved version of the Backward II interface. But I hope I will be able to write a new
Preferences include the general options and the default set up. Please remember
the the default set up is used when you run any non recognised programs (including the
GEM desktop). So if you have a default-set up with no cache and/or a 68030 running at
8 Mhz, you will have a slow Falcon. In order to avoid difficult situations, GEM and
hard drive are always turned on for the default set-up.
You can press one the Shift keys when the Backward message is displayed at boot
time, it allows you to disable Backward: general options are all turned off, TOS patches
are off, frequency is 16Mhz, caches are on etc...
Backward is able to recognize programs and to adapt its setup accordingly. For
such a recognition, Backward uses keys, which are extracted from the program. There
are two kinds of links : floppy and program links.
A floppy link associates a set up to a floppy disk. When you boot up on a floppy,
Backward reads the boot sector, extracts some keys and check the presence of those
keys in the library. Floppy links allow you to use any Backward options, but they are
only recognized at boot-up.
A program link associates a set up to a program file (e.g.: *.PRG or *.TOS). When
you run a program (from the desktop, or in the AUTO folder while booting), Backward
III extracts keys from the file and checks for their presence in the library. Program links
do not allow all Backward III options (e.g : changing memory size or deactivating
GEM), but they allow you to use program on an hard disk.
When you start BACKWARD.APP, the screen displays a menu bar and a window
showing the library content (for the moment, you can use only one library which is
stored in BACKWARD.DKS). The demo version allows up to 20 set ups in the library
and the registered one allows up to 2000 (more on request).
Only the name of a set up is displayed in the window. They are sorted in
The Menu Bar:
In the first menu (BACKWARD) you find the classical 'About...' entry and your
The second menu (File) gives you access to :
- Save library : writes immediately the library to the disk.
- Save Preferences : save the default set up and the general options. The default
set up can be modified when there isn't any selection.
- Quit : go back to the Desktop.
The third menu (Library) gives access to :
- Add a set-up... : for adding a new set up in the library.
- Delete a set-up : for removing the currently selected set up.
- Re-scan disk : read the floppy and tries to find the associated set-up. Sadly there
is no equivalent option for program links.
The fourth menu (Options) :
- Register.. : gives access to the registration box. You have to enter your name and
your key for registering a demo version (beware, case are significant).
- Set up.. : allow you to change the selected set up (or the default set up if none is
- General Options ...: gives access to the options dialogue box which contains
options shared by all set ups.
- Then you have the pre-sets which allow you to choose easily a set up.
The Library Window:
The only window shows all setups present in the library sorted by name. Arrows
allow you to change the part of the library displayed. If you press a alphabetical key, the
contents of the window change to display setups starting with this letter.
A single click on a setup selects it, and a double click edits the setup.
When the library is modified, the window title changes to '* Library' as a reminder.
The setup dialogue:
This is the essential part of Backward; in this box you define the various options of
the emulator which will be used when you run the associated program or floppy.
A the top of the dialogue, there is a text field where you can enter and edit the
There is also a button : 'Link to ...'. Each set up must be linked to a floppy or a
program, otherwise it will useless. If you press this button, a alert box ask you whether
it is a floppy or a program link. If you select floppy, Backward reads the floppy in drive
A and associates the setup to this disk. If you select program, the file selector is
displayed and you can select a program to which will be linked the setup.
Then you have various options which are grouped by category:
˙ MC 68030 : options related to the processor :
- Frequency : allows you to select the processor speed.
- Caches : allows you to select which on board caches are active. None means no
cache, Inst. means instruction cache only, Data means data cache only and both means
both caches. Most programs works very well with data cache active, but some do not
cope with instruction cache.
With a VGA display, a Falcon at 8Mhz with no cache is slower that a ST()
(approx. 10% slower). But with a VGA monitor, 8Mhz and data cache, the Falcon is
approximately as fast as an ST.
˙Hardware : options related to the hardware :
- Speaker : allows you to switch on/off the internal speaker.
- Hard Disk : allows to to ignore the hard drive. This option works only with floppy
links. If you keep the hard drive, the falcon always uses the AUTO folder and desk
accessories present on drive C.
- Video (STlow, STMed, STHigh, Def.): allows you to change the resolution (Def.
means that the resolution is not changed). When the program terminates, the previous
screen resolution is restored.
˙System : miscellaneous options:
- Sound errors (None/Corr./Spec./STE) : decides how bus errors are handled.
None means that nothing is done, when an error occurs, two bombs are displayed.
Corr. means that each access causing an error is correctly re-executed, this option slows
down your computer when they are many errors (e.g: digisound). Spec. means that
Backward tries to correct the program which causes such errors; it is the more powerful
option, it works great (good sound) without slow down. STE means that such errors are
simply discarded; as it implies that sound is of lesser quality, use this option when the
others are inefficient.
- Memory : allows to select the memory size. This option works only for floppy
links. Only very old programs requires a specific amount of memory (mainly 512Kb).
- TOS Patches : corrects the some system calls. I have heard that previous
Backward versions had some problems with some games written in basic when this
option was on. Sincerely, this option should ALWAYS be turned on, as the Falcon
TOS is a complete mess.
- GEM : allows you to deactivate GEM (works only with floppy links). It frees
32Kb in the lower part of the memory. Some old games requires this (it allows you to
run games which works only on TOS 1.00, such as Bionic Commando or Star Trek).
Sadly, there is no perfect method for finding which setup is required for a
program. There is two main methods : either you start with a minimal setup (preset
'Falcon') and you change some options till the program runs, or you start with the
strongest setup (preset 'ST(e)') and you remove options. The first method gives best
performance results, but the second one needs less tries. Only one rule applies : if your
program do not work with the preset 'ST(e)', it is very unlikely it can be used with this
version of Backward.
Important note : even is the dialogue allows you to turn off GEM and hard disk in
the default setup, they are always kept on to avoid troubles.
General options :
There are three options :
- Multiscan screen. It concerns VGA, SVGA or Multiscan screen owners. When it
is turned on, Backward emulates PAL (i.e. 50Hz refresh rate). If your screen do not
support 50Hz Vertical Frequency (i.e. rolling screen), turn this option off.
- Skip IDE drive. This option prevents the TOS for checking IDE drives. Choose it
only if you have no IDE drive (otherwise it will be hidden).
- no ATARI Logo. This option disables the display of the ATARI Logo at boot
When GEM is deactivated, as the GEM desktop cannot be used, MiniDesk is
provided instead. As its main goal is a low memory usage, the interface is rather
simplified. It displays all directories (in brackets such as [AUTO]) and programs. The
arrows allow you to change the current selection. Pressing Enter on a directory opens it
(the directory [..] allows you to return to the previous one), and pressing enter on a
program runs it.
Alphabetical keys change the current drive accordingly. GEM program won't work
when run from MiniDesk.
The Patch kit:
This kit contains two programs : PATCH.GP and UNPATCH.GTP. Patch executes
a patch script to modify a program and unpatch removes those modifications. Patch
files use the extension .PTC; they are ASCII files containing patching orders.
The PATCHES.LST file contains the list and short description of patch files. If you
want to apply a patch, just drag the corresponding file (e.g. KILCLOUD.PTC) on the
PATCH.GTP icon (take the time to make a backup copy of your program). Then
follow the instruction on the screen. If you want to remove the patch, drag the same
script file on UNPATCH.GTP.
- *.PTC files (generally) work only with a given version of a program.
- a patched program is very unlikely to be working on a ST or without Backward,
but UNPATCH can restore it.
- those patches take a lot of time and are not guaranteed (still some troubles with
- they are some securities : PATCH won't do patches if it does not recognize a
program, but if the patch failed, run unpatch to make sure that all patches are
- programs listed in PATCHES.LST REQUIRES to be patched in order to run on
To be registered please send 100FF (or equivalent in your currency) to the
following address :
Mr Cyrille Dupuydauby
53 domaine des aigles
You will receive a disk with the latest released version and a registration key and
support (e.g. you can send me copies of non-working programs).
Beyond the horizon:
Upgrading from Backward II :
The program CONVERT.PRG converts a Backward II library
(BACKWARD.DAT) in a Backward III library (BACKWARD.DKS). Simply copy it
where you have your old library and run it, the Backward III files will be automatically
Backward offers a unique ability : using any TOS 4.xx on any Falcon. Simply get a
copy of TOS 4.xx roms in a file, name it ROM.IMG and copy it on your C drive (or
Backward floppy if you use floppies). Beware, Backward III uses ROM copies;
TOS.IMG files are RAM version of TOSs.
This feature will be fully integrated in the future, but you can already replace
MiniDesk by the shell (non-GEM) program you want. Simply copy your shell (e.g:
COMMAND.PRG) where MiniDesk is stored, and rename it to MINIDESK.PRG.
As my free time is dramatically shrinking, I cannot make any plan beyond next
Backward version. Since the last two years, 75% of the time passed on my Falcon was
devoted to Backward.
At least, I hope to find the time to rewrite the library manager, which currently
prevents Backward III to be used at its full power.
This version is dedicated to all my registered users.
See you soon !
© marko latvanen / atari forever 1999-2006