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Alive 6
                        Some minor hints and notes on

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           assembled mainly from the Profibook ST-STE-TT from
           Julian F.Reschke, Hans-Dieter Jankowski and Dietmar
           Rabich (Sybex Verlag 1991) and various other sources
           including magazines by The Paranoid.

           For Ray of .tSCc.

                        Think you can handle it ?!

                         (of the Lunatic Asylum)

Note of STS : here's the second tutorial offered in this issue. Again you can 
access all chapters  via the  menu below while  in each  chapter two links will 
allow to get back to this file or further into the next part. Enjoy again !

 Links to various chapters :

1. The Atari TT Hardware
2. Two kinds of RAM in the TT
3. TT Graphics subsystem
4. Blitter
5.  DMA-Sound
6.  Other specifications of the TT to mind about
7. Epilogue


The Atari TT or TT030 is a powerful workstation initially planned to approach
the Unix-market in competition to SUN Microsystems and Hewlett-Packard, which
were producing professional Unix-workstations based on Motorola 68000 and
Motorola 68020 processors in the eighties.

The Atari TT was initially designed to feature a Motorola MC68020, clocked at
16 MHz, a Motorola MC68882 FPU, also clocked at 16 MHz, and to run on a
version of System V by AT&T. A TOS-compatible operating systems was initially
only thought of either as a nice extension or as a last resort if everything
else failed.

The Atari TT that was commonly available in the stores looked slightly
different after all: Instead of an 68020 as planned, it featured the even
more powerful MC68030, which was also not clocked at 16 MHz anymore but
ran at a full 32 MHz, just like its companion, an MC68882 at 32 MHz.
Instead of System V, the computer was sold with a version of TOS,
initially named TOS030, later on renamed to TOS 3.0x.

However, hardly any software for the Atari ST ran on this system, even
though the hardware was "similar" and the operating system compatible.
Atari finally decided to release an awful lot of programmer's documentation
on how to handle BIOS, XBIOS, GEMDOS, VDI and AES in a way to ensure
maximum compatibility.

Which was a good idea just as well.

Games and demos usually refuse to run on the Atari TT. Reasons are
numerous, but in some respect, parts of games or demos could have
easily been designed in a way that they do run on a TT. Then again,
certain aspects of game- or demo-writing would require a lot of
reprogramming to make them TT-compliant.

This little documentation is meant to introduce all of the TT-hardware
that's relevant for games- or demo-programmers, i.e. graphics, timing
and sound-hardware as well as certain approaches to make ST- and STE-
programs TT-compatible.

It will also feature certain TT-only aspects, in what way they could
be used as an enhancement without losing ST-compatibility as well as
the problems you might encounter when trying to use them.


Certain names or brands will be used in this documentation to adress
the different Atari computer models that may be mentioned in this
- Atari TT
  This will refer to the Atari TT or Atari TT030 as it was sold in
  large amounts, meaning a 32 MHz 68030 CPU, a 32 MHz 68882 FPU,
  at least 2 MB of ST-RAM, optional TT-RAM, equipped with a
  TT-Shifter. None of this documentation will actually apply to a TT
  using a graphics card.
- Atari STE
  This usually refers to a computer of the Atari STE series, equipped
  with an 8 MHz 68000 CPU, the STE-shifter and a random amount of RAM.
  If required, the Atari MegaSTE series, equipped with a 16 MHz 68000
  and a 16KB 2nd level cache will be adressed explicitely since it
  also features certain aspects of the TT hardware (VME-related).
- Atari ST
  Means one of the ordinary Atari ST series computer, including Atari
  260, 520, 1040 ST, STf, STm and STfm as well as the Mega 1, Mega 2,
  Mega 4 series, sometimes officially named Mega ST 1, 2 or 4.
- Atari Falcon
  Refers to an Atari Falcon030. This machine is much more similar to
  an Atari STE than to an Atari TT, however, the graphic chip of the
  Falcon, the VIDEL, is capable of "emulating" certain resolutions of
  the Atari TT and it also has an 68030 CPU that can be equipped with
  an 68882 FPU.

Alive 6