
z26 -- An Atari 2600 Emulator (0.88)
------------------------------------

Copyright (C) 1997-1998 by John Saeger (john@whimsey.com)

Home Page:  http://www.whimsey.com/z26.html


Introduction
------------

z26 is a small, fast, easy to use Atari 2600 emulator that runs on a DOS
platform, including a Windows 95 DOS box. z26 supports full Atari 2600
sound emulation using a Sound Blaster.


System Requirements
-------------------

z26 will run at full speed on virtually any Pentium class platform with
a reasonable (PCI or better) video subsystem. It also runs fine on the
AMD 5x86 machines, and even on some fast 486's. It runs very close to
full speed on an Intel 486 DX4-100 with a VLB video card. 

z26 supports the use of a Sound Blaster card. It requires a Sound
Blaster with at least version 2.00 DSP. This includes SB 2.0, SB-PRO,
SB-16, and SOME older Sound Blasters. It should also run on more recent
models as well.

If you don't have a Sound Blaster or a compatible sound card, z26 will
make an attempt to use the PC speaker to generate sounds. Try not to
expect too much from the speaker though.


Startup
-------

At the command line prompt type:

>z26 filename

where filename is the name of a "standard" Atari 2600 .bin file. For
example: 

>z26 demonatk.bin

will run Demon Attack. You're on your own finding the .bin files. But if
you follow the links on the z26 home page, eventually you may get lucky.


Getting Help
------------

If you type

>z26

without a filename you get a short help screen describing the available
controls and command line options. The screen currently looks like this:


z26 -- An Atari 2600 emulator (0.88)
Copyright (C) 1997-1998 by John Saeger

Home Page:  http://www.whimsey.com/z26.html

    F1 -- reset        F2 -- select
    F9 -- B/W         F10 -- color
     p -- pause     ENTER -- resume
 SPACE -- fire        ESC -- quit game

     = -- PCX screen capture

The Atari joystick is emulated with the arrow keys.

Command Line Switches (put before filename)

 -0    -- player 0 hard
 -r    -- do not wait for VGA retrace (full speed)
 -q    -- quiet (no sound)
 -v    -- verbose (show diagnostic messages)
 -f<n> -- run emulator for <n> frames and display timing results
 -c    -- show contributors (please do!)


For more detailed information please see the FAQ which can be found on
the homepage.  Otherwise, email me and I'll try to answer your question.


Troubleshooting Sound Setup
---------------------------

If you run z26 and don't hear sound when you think you should, the first
thing to check is to make sure the volume is turned up. If you're
running under Windows 95, use the system volume control and make sure
the Mute box is not checked. Also make sure the Wave Balance volume is
turned up and that its Mute box is not checked. If you're running under
DOS, use the volume control (mixer) program that came with your sound
card.

Failing that, try running z26 with the -v (verbose) command line option.

If you get the message "Sound Blaster too old!", maybe it's too old. You
need a Sound Blaster with at least version 2.00 DSP to run z26.

If you get the message "Sound Blaster not found." then either you don't
have a Sound Blaster, or there's a problem with the environment string.
z26 expects you to have an environment string set with the configuration
of your Sound Blaster. If you're running under Windows 95, this usually
is not a problem because Windows 95 seems to set up the environment
string automatically. If you're running under DOS, the environment
string is usually set up during the Sound Blaster installation
procedure.

To find out if your environment string has been set, type

>set

at the command line prompt.  Or type

>set | more

if there's too much information to display on a single screen.

You should see an entry something like this somewhere in the output:

BLASTER=A220 I10 D1 H7 P330 T6

If you don't, that's the problem. Otherwise the information in the
environment string may not match the actual settings on your Sound
Blaster. In either case, re-do the installation procedure for your sound
card to correct the problem, or set up the environment string manually.


More About Sound
----------------

z26 uses the tiasound library by Ron Fries to emulate sound. According
to Ron, the optimum playback sample rate is 31400 samples per second.
This is the "natural frequency" of the Atari, the frequency at which the
sound generator in the Atari originally ran. So if your Sound Blaster is
capable of playing sound at this rate (and most modern Sound Blasters
are), we use this rate. There are a few older Sound Blasters that z26
supports that won't run at this rate. These Sound Blasters are run at a
rate of 15700 samples per second. This causes only a small degradation
in the quality of the sound.

We also use tiasound's ability to generate sound in real time. This
means we can use very small sound buffers. This allows z26 to be more
responsive to rapid changes in the sound that some games call for. z26
currently uses a sound buffer of 128 bytes divided into two parts,
giving it an effective buffer size of 64 bytes.


Warranty
--------

z26 is provided without a warranty of any kind, either express or
implied. Neither John Saeger nor anyone who has worked on the code may
be held responsible for any damages, either direct or consequential,
caused by the use of z26. 


Freeware
--------

z26 is freeware and may not be sold.


Credits
-------

z26 is based on a program called A26 version 0.15 (C) 1996 by Paul
Robson (autismuk@aol.com). A26 is the original "small and fast" DOS
based Atari 2600 emulator. 

PCX screen capture is (C) 1997 by Ronnie Green (ender@abts.net).

Atari 2600 sound emulation is (C) 1996-1997 by Ron Fries
(rfries@tcmail.frco.com).

Thanks!!!


