PCjs is an open-source collection of classic PC hardware and software emulators that lets users run vintage operating systems and applications directly in a web browser.
The project emulates historical IBM PC-compatible machines, including processors, graphics, storage, and other hardware, allowing visitors to experience software from the early personal-computing era without installing it locally.
It also provides a large archive of vintage programs, documentation, and machine configurations for exploring computing history.
About PCjs
The PCjs Project is a collection of classic computer simulations built entirely with JavaScript. It’s an open-source project hosted on GitHub and available to explore online at PCjs.org.
The idea behind PCjs is pretty simple: bring old computers back to life in the browser. You can explore how classic machines worked, experiment with different hardware setups, and run or study software from an earlier era of computing—all without needing the original hardware.
The simulations work across modern desktop and mobile browsers. Each virtual machine is defined using simple XML files that describe its hardware components and capabilities, making it easier to create and configure different systems.
The Challenger 1P
The first PCjs simulation was C1Pjs, an emulation of the Challenger 1P, a 6502-based computer released by Ohio Scientific in 1978. The first version, C1Pjs v1.0, launched in July 2012 and marked the beginning of the PCjs project.
IBM PCs and Compatible Machines
PCjs later expanded into PCx86, which emulates classic IBM computers such as the original IBM PC, PC XT, and PC AT, along with compatible systems like the COMPAQ DeskPro 386.
PCx86 supports several Intel processors, including the 8088, 80186, 80286, and 80386. It can even recreate the graphics and text produced by vintage display standards such as MDA, CGA, EGA, and VGA.
The simulations can include hardware such as disk controllers, serial and parallel ports, and other motherboard components. There’s even a built-in PCjs Debugger that lets you see and interact with the simulated hardware.
Over time, PCjs has grown far beyond early IBM computers. The project now includes simulations of minicomputers, programmable calculators, terminals, LED displays, and classic arcade games.
For anyone interested in computing history, vintage hardware, or simply curious about how early computers actually worked, PCjs offers a fascinating way to experience that history directly in a web browser.
