Steve ][ – A fast Apple II emulator

An unexpected highlight at KansasFest 2020 was the introduction of a speedy, new Apple II emulator by Tamas Rudnai, dubbed “Steve ][.” Written for macOS Mojave and later, Steve ][ has a modern interface with many options and works with the popular WOZ format.

According to Tamas, “Steve ][ tributes the two co-founders of Apple, Steve Wozniak and Steve Jobs. Wozniak was the evil genius hardware designer and inventor, while Jobs was the brilliant marketing and visionary person behind the most successful company in computer history. Steve ][ lets you travel to 1977 and bring an Apple ][ back with you to 2020, adding 40 years of technology enhancements to it. It speeds up the 1.023 MHz legacy hardware to a 1.3 GHz modern computer. That is a 1300x speed increase thanks to some clever emulation techniques, including memory handling tricks and branch prediction optimizations to utilize the full power of a modern host computer.” During his presentation, Tamas calculated that software which would normally take four hours to run on the original Apple II would only take 11 seconds on Steve ][.

What I found especially interesting was Tamas himself and the story of what inspired him to write Steve ][, so I asked him to elaborate. Tamas replied, “My father was a mechanical engineer, plumbing engineer, designing heating and water supply system for large buildings. He bought an Apple ][ in the 1980s to speed up his work,” said Tamas Rudnai. “This was not easy because Eastern Bloc countries were not allowed to buy American computers, so we smuggled in a Taiwanese clone piece by piece from Germany. My father wrote the software by himself and was able to reduce the time needed for a budget calculation from three weeks to just three days. One iteration of that calculation lasted three to four hours. I remember, he started the program and then came to the kitchen for a lunch, waited my mom to finish cooking, eat everything, had a nice coffee, then talking to us, and the program was still running. When he passed away I found the old Apple ][ in the basement and all of these memories rushed into my mind. I was really curious how long would that take to run that software in modern hardware? You know, if that Apple ][ was built today’s technology….”

Tamas continued, “Steve ][ is capable of emulating an Apple II, Apple II Plus and Apple IIe, depending on which ROM is selected from the Config menu. It includes a 64K memory expansion card emulation which is also works as a 16K Language Card and an 80-column video card. It fully supports GR and HGR graphics video modes in Color and Mono monitor modes. In Mono mode, one can select between Green, Amber and White phosphor monitors. There is also a CRT mode, which is a graphics rendering technique to get the real feel of old CRT monitors, complete with scan lines and a tiny little bit of blurry effect.

The CPU speed selector is conveniently accessible from the middle of the toolbar as a slider. When it is moved all the way to the right, the roaring 1.3 GHz is achieved. A bit lower or higher speed than this is possible, depending on the host computer and which apps are running at the same time.

Steve ][ also includes some interesting features, like CPU modes. In Normal Mode, the screen is refreshed at 30 FPS and input latency is about 33ms, which is prefect in normal situations. We can switch to Game Mode, which doubles the screen refresh rate and lowers input latency to 1.5ms. That means that games react faster for keyboard and joystick / mouse inputs.

Another CPU mode is ECO Mode, which is similar to Normal Mode, except when the Apple II is only waiting for keyboard input, it sleeps the machine, therefore it only has minimal energy impact on the host computer. However, when the user starts typing, it automatically unpauses and lets it run at the speed determined by the Speed Selector. And because of that, we can use Steve ][ on an airplane for a longer period of time while enjoying quick burst operations, such as compiling Assembly source code with Merlin.

Disk operation also provides some notable features. In Normal Mode, one can hear an authentic disk sound which can be turned on or off. Furthermore, Quick Disk Mode speeds up disk operations drastically. For example, the DOS 3.3 Master disk with Integer BASIC can be fully loaded in less than a second.

Steve ][ natively supports the WOZ 1 disk image format, and DSK / DO / PO formats. These latter formats are automatically converted to WOZ internally, and it is done so quickly and transparently that it will not be noticed.

Steve ][ is designed to run on macOS Mojave 10.14 and higher, and it is released as free and open open-source software under the GPL v3 license. Download the source code from GitHub now, with binary distribution available soon:

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About the Author

Brian Wiser

Brian is an A.P.P.L.E. Board member and Managing Editor of Call-A.P.P.L.E. magazine. He is a long-time Apple consultant, historian and archivist. Brian designed, edited, and co-produced several books including: "Cyber Jack: The Adventures of Robert Clardy and Synergistic Software", "Synergistic Software: The Early Games", "Nibble Viewpoints: Business Insights From The Computing Revolution", "What's Where in the Apple: Enhanced Edition", and "The WOZPAK: Special Edition" – an important Apple II historical book with Steve Wozniak's restored original, technical handwritten notes as well as a forward from Steve Wozniak and other Apple legends. Brian also co-produced the retro iOS game "Structris." Brian was an extra in Joss Whedon’s movie “Serenity,” leading him to being a producer/director for the documentary film “Done The Impossible: The Fans’ Tale of Firefly & Serenity.” He brought some of the Firefly cast aboard his Browncoat Cruise and recruited several of the Firefly cast to appear in a film for charity. Brian speaks about his adventures at conventions around the country.