Rainbow 95 - The Atari 8-Bit Emulator for Windows
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Version 1.36



Appendices
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A - Rainbow technical details
-----------------------------


For those who like to revel in technical specs, here's the list
for Rainbow.

Hardware:

  · NMOS 6502 processor 
  · Accepts 400/800 and 800XL/130XE OS 
  · Emulates the 5200 video console system 
  · 48K RAM for 400/800 machines; full 64K RAM for 800XL; full
    128K RAM for 130XE
  · NMI and IRQ interrupt emulation
  · 8K and 16K cartridge support; 16K and 32K cartridges for 5200
  · 16K Super Cartridge support
  · Low level SIO emulation allows access to virtual disk images
  · Supports single and enhanced density images and ATR images
  · Disk drives D1: and D2: available
  · Import/export files to and from your PC hard disk
  · Full keyboard

Graphics:

  · 256 Atari colours
  · Complete playfield generation (ANTIC modes 2 to 15)
  · Narrow, Normal and Wide playfields
  · GTIA support giving 3 extra colour modes
  · Colour artefacting in GRAPHICS 8
  · Display List Interrupts  
  · Player/Missile Graphics
  · Full Player/Missile/Playfield collision detection
  · Player/Missile priorities (mutually exclusive and
    non-exclusive)
  · Fine scrolling
  · PAL/NTSC screen option

Others:

  · Superb 4 channel sound using POKEY samples
  · POKEY timers 1, 2 and 4
  · Four joysticks support using keypad
  · Four paddles support using mouse  





B - Why won't this game work???
-------------------------------


Okay, you've tried everything and your favourite game still won't
run properly. Go through the following checklist.

  - Try the game with and without BASIC inserted. On the XL, keep
    the OPTION key (F1 on the PC) pressed to disable BASIC when
    re-booting.

  - Does it need an XL/XE machine?

  - Does it need the very old 'A' version of the 400/800 OS? Some
    software did do naughty things like jumping in and out of OS
    routines when they should have used vectors.

  - If you're trying to run a BINARY FILE, then the loader/DOS
    you use may affect it. Some games I've tried simply won't run
    using the L option in Atari DOS 2.5 but do run successfully on
    another e.g. SmartDOS. The best loaders are the tiny ones which
    take only a second to boot up. Experiment and see which work best
    for you.

  - Some games may need the 'Every' frame option to work properly
    or for the graphics to behave and look right.

  - Are you sure your file or disk image is not corrupted?

  - Turn 'Cheat Mode' off.

  - Have you got the correct joystick/paddle active?

  - If the screen seems unstable or blank, try checking the the
    'PAL' option under 'TV' menu.

  - If movement seems wierd in 5200 mode then try using 'Pad0'
    which imitates the joystick as an analogue device using the
    mouse.


If all this fails, then it's down to the limitations of the
emulator. Although Rainbow is a very good emulator, at the end of
the day, it's just that... an approximation of the real thing. 

Some games may include illegal (or undocumented) 6502 machine
code instructions to protect the code against hackers. Since they
are undocumented, their behaviour is not well known but a good
attempt has been made to include all of them in Rainbow, the
information coming from a number of sources (with inevitable
contradictions...). This is just another possible reason why some
games won't run properly.





C - The 'Atari computer crash' alert box
----------------------------------------


Now and again, you will encounter this alert box. Although it
looks horribly ominous, it's nothing to get worried about and no
damage is done to Rainbow or your PC.

It means the CPU has just executed an illegal opcode which is
known to freeze the machine. So rather than let the emulator just
sit there and do nothing, it informs you of this.

The only way out of such a crash is to switch the emulator off
and on, i.e. re-boot. 

If you hold the Control key down on the re-boot, the cartridge is
removed and drive#1 turned off. This is useful to get out of a
continual crash sequence, e.g. bad boot disk.

Pressing SYSTEM RESET to get out of a game can often result in a
'crash' and is nothing to worry about. Pity Rainbow can't
recreate some of those spectacular graphics when a real 8 bit
crashes... I used to sit there for hours engrossed in crashing
the machine just to see the pretty colours.

Ahem...





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Comments and suggestions (please say you are a PC user) to...

E-mail: chris@shenleyfields.demon.co.uk
WWW   : http://www.shenleyfields.demon.co.uk/

Rainbow (c) 1995-7 by Chris Lam.

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