Help

Technology, Performance and Optimization

This site is using our highly optimized JSDOS library

We made huge improvement on JSDOS library:
Compared with the original JSDOS library that only outputs in mono, we support stereo output in sampling rate of 44100. Also solved audio popping and crackling, and reduced audio delay significantly.
Support for 3Dfx Voodoo 3D acceleration, resolution upscaling and anisotropic filtering.
Gamepad support.
Roland MT-32 and General MIDI are fully supported. For General MIDI you can select from soundfonts with different qualities. By default, games are set to use General MIDI first then MT-32 if both are supported.
The FPU part has been rewritten, games with special instructions are now working perfectly.
Screen lag has been reduced by more than 50%, allowing games that were originally poor experience can run normally.
We fixed bugs that caused the mouse pointer to move incorrectly in some games.
A lot of code optimization work has been done, making some games perform about 5%-10% better than the original library.
Added disc switching function and compressed CD audio support, reduces the image size while maintain the original game experience.

Even with above optimizations, running games in the browser still requires a CPU with strong single-core perfomance.
(During the CPU technology high speed development in the 90s, the performance of CPU improved rapidly. For example, the game in 1994 and the game in 1996 had very different CPU requirements. So your current processor may not run all games smoothly.)
According to our estimates, the CPU 5 years ago is equivalent to 486 DX66 level, and the CPU 2 years ago is equivalent to Pentium 100 level. We expect CPUs that will be released this year to run all games smoothly under SVGA resolution.
If a game cannot run smoothly, please lower the resolution in the game settings.

Play Games and Save Functions

The first time you start a game, you need to download the necessary game and system images. If it is a complete CD version, the CD image will be downloaded and unzipped additionally.
After the game starts, the function menu will appear above the game window.
For multi-CD games, you can select the specified CD in the menu after the game prompts you to change the disk. Once selected, the CD image will be downloaded and unpacked on demand.
CD image will be cached, so there is no need to download and decompress it the next time you open it. But once other CD version game is played, the old game cache will be cleared.
The Save function inside the game does not save the game progress in the browser, so you need to manually hit save button in the function menu. If you directly close the browser without saving, the progress will be lost.
The cloud save function is only available to Gold members. Save files can be downloaded and saved locally. Local saves can also be uploaded to the browser. Note that the emulator will restart after uploading.
Save file is in standard ZIP format.