----------------------------------------------------------- Known problems: ----------------------------------------------------------- Video problems: The main problem with video has to do with two things: performance and synchronization. Performance is mainly governed by how well your system can convert video bitmap data between different modes when running in a window, and by how compatible your video card is when running in full-screen mode. If your window causes the mouse pointer to flicker in windowed mode, then it's likely that the system has to use too much CPU time to convert video data and/or the blit to the window is being emulated by DirectDraw--rather than being performed using the video hardware. If the emulation runs slow even in full-screen mode (for which the emulation was designed), then you are either using a CPU which is too slow (an old Pentium or older), or your video card is too slow. Synchronization problems can arise because of conflicts between the emulation timer and the monitor refresh rate. To achieve smooth video on your desktop window, you may wish to change the refresh rate of your display adapter to match the emulation (60 Hz for NTSC). Changing the refresh rate, however, may have adverse effects on your monitor--so be sure to check the manual that came with your monitor and see whether it can handle being set at that rate. If you run in full-screen mode, you cannot change the refresh rate of the monitor (so, if the emulation runs too fast, for example, you should turn the "Smooth Video" option off). If you are using Windows NT or 2000, you should try to acquire the latest drivers for your video card (especially if you are using an ATI video card). If you have an old ATI card and Windows NT, then you should probably stick with full-screen mode. *** Audio problems: The audio is prone to distortion on slower systems, and even (very briefly) at odd times of faster systems. This is possibly indicative of the operating system (in particular, if the system is using networking). The emulation is quite sensitive to changes in CPU usage, but runs at a normal priority for the sake of cooperative multi-tasking. The audio is also scaled to the monitor frequency when the system is running in "Smooth Video" mode. This is a matter of design and cannot be resolved without distorting the audio even more. Audio can also suffer performance degradation due to problems with the video performance. ----------------------------------------------------------- Atari Computer Emulation: ----------------------------------------------------------- Rescue on Fractalus has some video glitches. Symptoms: Strange bars appear on the screen from time to time and in various places. Cause: Unknown. Status: Pending. *** Mail Order Monsters has a lot of odd colors. Symptoms: Strange bands of colors appear at times, and the battle menu doesn't have the proper colors. Cause: Draw routine does not currently support on-the-fly color changes. Status: This should be fixed in the next major revision. *** DOS won't write, format or change density. Symptoms: Disk operations sometimes mysteriously fail or return an error when storing or copying data is expected. Cause: Operations not currently supported. Status: This will be implemented soon. *** Diagnostic for the Atari 400/800 shows "NO GTIA". Symptoms: See above. Cause: No support for GTIA modes in "low" resolution (only "high"). Status: Support for this feature is not currently planned. *** XL Mode: XL mode has not been thoroughly tested, albeit the diagnostic test says the ROM, memory, etc. is okay. The Eidolon (which requires XL memory) is functioning, so it must be at least partially working. *** Misc.: Mosaic and XE modes have not been tested at all and may not work. ----------------------------------------------------------- 5200 Emulation: ----------------------------------------------------------- Asteroids lacks control. Symptoms: The ship becomes stuck in various states of rotation. Cause: Unknown. Status: This seems to be a flaw in the original game. *** Hard errors from Diagnostic Cartridge test of ANTIC. Symptoms: Returns codes "30 01 34 01". Cause: Unknown. Status: Pending. *** Goal post in Ballblazer is unstable. Symptoms: The left goal post flickers or becomes a double-image at various times--especially when up close. Cause: Unknown. Status: Pending. *** Galaxian ship leans right. Symptoms: The ship always veers right. Cause: Unknown. Status: At first glance, there doesn't appear to be a center state in the original code. Still pending, though. *** Top line of Astro Battle ships flicker in Gorf. Symptoms: On half the video frames, the enemy ships appear to be an "=" character. Cause: Video timing-related. Somewhat technical. Status: The emulator probably needs a redesigned draw state engine to completely work out this bug. It's even more sensitive than the 400/800 version--which doesn't seem to show symptoms. *** Ship moves too fast in Gorf. Symptoms: The ship moves to the extreme position whenever you press a directional key. Cause: Input support is incomplete. Status: Still working on it. *** Buckets move to fast in Kaboom! See the above notes on Gorf. *** Looney Tunes Hotel halts at start. Symptoms: Screen freezes and the status bar reads "Halted". Cause: Unknown. Status: It may be an unplayable version. The "alt" version seems to work fine, though. *** Millipede directional gets stuck to the right until you press a direction. Symptoms: Any time the game restarts, the directional gets stuck to the right until you press a direction. Cause: Unknown. Status: Working on it. *** Miniature Golf has weird-looking colors. Symptoms: Lots of dark red and blue lines appear on the screen. Cause: Video artifacting. Status: This is part of the emulation design. If you want non-artifacting, you must turn it off (in the settings). *** Ms. Pac-Man gets stuck going left. Symptoms: The player moves left unless pressing right for some period of time. Cause: Unknown. Status: Pending. *** Pengo sticks to the right for a little while. Symptoms: When first starting, the player moves right for a short period of time. Cause: Unknown. Status: Pending. *** Pitfall! doesn't respond to pressing Start button. Symptoms: Pressing the Start button has no noticable effect. Cause: Unknown. Status: Pending. *** Car does not gently steer in Pole Position. Probably related to the input problem as stated with Gorf (above). *** Popeye immediately halts at startup. Symptoms: See above. Cause: Unknown. Status: Pending. *** Q*Bert only moves up and down. Symptoms: Left and right have no noticable effect. Cause: Unknown. Status. Pending. *** Rescue on Fractalus has some video glitches. Symptoms: Strange bars appear on the screen from time to time and in various places. Cause: Unknown. Status: Pending. *** Robotron doesn't shoot. Symptoms: Robotron can't shoot anybody. Cause: Input support not complete. Status: Pending. *** Player can't shoot in Space Dungeon. See Robotron. *** Sport Goofy halts at the start. See Looney Tunes Hotel notes (above). *** Star Trek won't start. Symptoms: See above. Cause: Unknown. Status: Pending. *** Star Wars Arcade doesn't control right. See Gorf notes (above). *** Super Breakout doesn't control right. See Gorf above. *** Super Pac-Man veers up and left. Symptoms: The player continuously moves up and left unless pointed down or right. Cause: Unknown. Status: Pending. *** Tempest veers to the right for a while. Symptoms: The directions seem stuck on right unless you press left and until you start playing. Cause: Unknown. Status: Pending. *** Wizard of Wor doesn't work. Symptoms: Player can't enter the game. Cause: Input support not complete. Status: Pending. *** Monsters don't appear in Wizard of Wor. Symptoms: Monsters appear to be invisible. Cause: Unknown. Status: Pending. ----------------------------------------------------------- If you would like to make some remarks about this emulator, please send me a message (at mpfenton@hotmail.com). Any input is appreciated. -----------------------------------------------------------