![]() Fortunately, I was able to rely on the earlier work that had been done by Mike Fort for the Mini vMac emulator. The PCE emulator I had been using implemented the serial mode of the Zilog chip, but not the SDLC mode. The Z8530 SCC chip on on an Apple Macintosh 128K/512K motherboard It frames packets, senses the media, avoids and detects collisions and computes frame checksums. In this mode, the chip is quite sophisticated. Yes, it does serial communications, but it also has a much more complex mode called SDLC that forms the backbone of the LocalTalk network. ![]() The Macintosh uses a chip called the Zilog E8530 SCC, a master-of-all-trades. I suspected that expanding my serial port demo to a LAN would merely involve shuttling serial data from one emulated Macintosh to several others, a trivial modification from sending it to just one, which I had already demonstrated. This simplicity lead me to believe that LocalTalk was plain old serial communications, with the transmit and receive lines electrically coupled into a common wire. At minimum, two Macintosh computers could be cabled directly together via their LocalTalk ports, making a small LAN of two, but more often, several computers were daisy chained together into a larger network. This port served double-duty: it could serve as a serial port or as an interface to the LocalTalk network, via Y-splitters. The Macintosh had a Mini DIN-9 port on its rear called the LocalTalk port. With LocalTalk, Maze Wars+ on the Macintosh supported up to thirty simultaneous players. Most of the computers in my museum lacked native networking capabilities, but the Apple Macintosh Plus, the crown jewel of my museum, had in its original form the ability to participate in a LAN called a LocalTalk network. Having gotten a pair of computers to play Maze Wars+ via a serial link, I set my sights on allowing several to do so. MazeWars+ between two emulated Macintosh instances, however, worked perfectly, proving the concept and leading me to want even more than two simultaneous players. ![]() Using my emulated modem, I was able to send a move across the line, but not quite reliably enough for a playable game (perhaps Battlechess required serial flow control, which my code did not implement).īattlechess on the Macintosh (left), Battlechess on the Amiga 500 (right) One of my early experiments involved running two instances of Battlechess, one on an emulated Macintosh and another on an emulated Commodora Amiga 500 in different browser tabs. This entailed a series of sub-hacks, including code to emulate a Hayes smart-modem and a virtual telephone exchange complete with made up telephone numbers in the ficticious 555 area code, which would allow one emulated computers to “dial” another via WebRTC data-channels. For instance: I made it so the emulated computers could talk to one another, via an emulated serial connection, from one browser window to another. Some of the features in my museum stem from a desire to leave no “what if” unexplored. This is the altruistic reason I share with others: in truth, the project was a selfish excuse for me to spend time tinkering with emulators, old software and Javascript, three things I really enjoy. I built an online computer museum, in JavaScript, so that people could interact with vintage computers and learn about them. I have a sweet spot in my heart for retro computers and software. On the surface, it is an simple web game with a retro feel, but how the first led to the second is a story of how one hack led to another, and then to another, and to many others still. Maze War is a historic game: it was the very first first person shooter game, released in 1974 for a computer called the Imlac. I have been working on a game that bridges the new to the old.
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