The History of Sega Genesis Emulators - Generator, Megasis and VGen

Today we will talk about the Generator, Megasis and VGen emulators.

Generator (1998)

Generator was an emulator that began in November 1997, created by James Ponder for a third-year college project. Its first version was released in March 1998 for UNIX (also running on Linux), and is among the first emulators for the Mega Drive. The project was born from open source and was built to be portable to other systems, such as Solaris, Net, Risc and Open BSD and RiscOS. Its first versions did not support sound, joypad, or save state, and had many bugs. In 1999, it gained ports for the Amiga by AmiDog and MacOS by Richard Bannister. In January 2000, it began to support sound by emulating the Zilog Z80 processor (by Neil Bradley's Multi-Z80) and the YM2612 chip (by Tatsuyuki Satoh). Also on the same date, it brought improvements for the M68k processor and palettes, among others. The first version for Windows was released in February 2000 under the name Generator32, and was created by Atani (it was closed in May). This version ran too fast for slow computers of the time, making it impossible to play anything that ran on it on modern computers. In April 2000, James released a second original port of the emulator, now for MS-DOS. This version had a fixed front-end that remained on the screen along with the game. It could be disabled by a keyboard shortcut. In addition, it also had NTSC/PAL video support, choice of region between US/EU and JP, full screen, reset, save state, screenshot and changes in video quality. Interestingly, James' emulator used its own 68k emulator, unlike other projects in the emulation world. It was even born with this proposal, to create processor emulation techniques (such as the 68k, for example) in an optimized way. In August 2001, Z80 emulation was added using Richard Mitton's Raze Z80. Its latest release was released in May 2003 for Linux and MS-DOS. The emulator also had several other ports, such as for Pocket PCs, iPAQ and Cassiopeia (the precursors of smartphones) in 2001 by Domenico Dato as PocketGenesis, two ports for Dreamcast in 2002 by Atani Software and MetaFox, for Playstation 2 in 2002 by Sjeep (and in 2010 also working on PS3s compatible with PS2, by aries2k), PSP in 2005 by sougen, and for UNIX by Christian Biere. Interestingly, in August 2003, Richard, who had ported the emulator to Mac, began to develop it himself (now for MacOS X). The emulator was last updated by Bannister in November 2022.

Megasis (1998)

Megasis (a mix of Mega and Genesis) was a Mega Drive emulator released on November 11, 1998, by Japanese developers JT and Bori. Interestingly, it was released for Windows, when at the time most emulators were released for MS-DOS. To run the emulator correctly, a Pentium 133MHz was required, and a Pentium 2 was recommended. A graphics card with DirectDraw support and, if possible, hardware acceleration was also required. For sound, DirectSound support was required. The emulator only really started working in the December 1998 update, when it started emulating the Z80 processor, and the PCM and FM sound chips, as well as fixing bugs in the 68k processor. The emulator had perfect emulation of the YM2612 chip (the console's FM chip), as well as stereo sound with up to 44,100hz quality. It also had save states (in .GSV and .KSB formats) and ran BIN and SMD game formats, as well as ZIP and LZH compressed formats. In addition, it also supported pause, reset, frameskip (with great acceleration for low-end computers), full-screen mode, multiple window modes, multiple game regions, sound recording in .WAV format, as well as FM and PCM sound recording, echo effect, changing the 68k processor clock, support for a six-button joypad, VDP emulation (which is the console's GPU), editing shortcut keys for various emulator functions, among others. Megasis had six versions in total, the last one being released in April 2001. From November 1998 onwards, fans were asking for a MacOS version. It seems that there was some indication from the creators for this at the time. In January 2000, it was posted on the project's home page that this version would be developed, but by June of the same year this information had already been taken down.

VGen (1998)

VGen or Virtual Genesis began to be developed in 1997 by Jason Meehan, and was released in March 1998 for MS-DOS. From May 1998, it began to run games via the command line, and in the November 1998 version it began to emulate sound through the Zilog Z80. The emulator also emulates the console's two sound chips, the PSG and the YM2612. The processors it used were Neill Corlett's 68k and Neil Bradley's Z80. VGen later provides a GUI that you control with the mouse, in addition to support for two controllers, supporting various joypad styles, various screen size modes and formats, frame rate, reset, up to 44,100hz sound, changing the game region and access to various technical information about the emulator, among others. Despite this diversity of options and information, the emulator was very deficient in speed, sound and compatibility, never leaving the alpha state. VGen also supported the Sega CD bios without running the games. It is said that the emulator would have been the first to run the Sega CD bios in the first version released in 1998, when in fact the first to run it was the NextLEVEL emulator in October 1997. Some information about Sega CD was brought by Christian Schiller, owner of the website Eidolon's Inn. In addition to the Sega CD, Master System and Game Gear were also planned for the emulator. The emulator ran on a Pentium 1 with 8Mb of RAM. Its last version was released in June 2001. As far as we know, the emulator would have had four versions released in total, the launch, two in 1998, in the months of May and November and the closing.