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Directory of C:\PCJS.ORG

The Original IBM PC in Your Browser

Welcome to pcjs.org and PCjs, the first IBM PC simulation to run in your web browser without any plugins. It was added to the JavaScript Machines project in Fall 2012. The project now includes:

  • PCjs, a simulation of the original IBM PC (circa 1981)
  • C1Pjs, a simulation of the OSI Challenger 1P (circa 1978)

All our simulations are written entirely in JavaScript. No Flash, Java or other plugins are required. Supported browsers include recent versions of Internet Explorer (v9.0 or later), Safari, Chrome, Firefox and various mobile browsers.

[Embedded IBM PC]

(If you see this message, PCjs may still be loading)

The simulation above features an Intel 8088 running at 4.77Mhz, with 64Kb of RAM and an IBM Monochrome Display Adapter. For more control, there are also Control Panel and Soft Keyboard configurations, featuring the built-in PCjs Debugger. For even greater control, build your own PC. The PCjs Documentation will help you get started.

The goals of the JavaScript Machines project are to create fast, full-featured simulations of classic computer hardware, help people understand how these early machines worked, make it easy to experiment with different machine configurations, and provide a platform for running and analyzing old computer software.


Some pre-configured machines are shown below, ready to run BASIC, DOS, Windows 1.01, and assorted non-DOS software.

Check out the rest of the PCjs Application, Boot Disk and Machine demos, including the IBM PC XT "Server Array" and Windows 1.01 "Server Array" demos of multiple PCs running side-by-side.


Below is the OSI Challenger C1P, another simulation in the JavaScript Machines project. It simulates Ohio Scientific's 6502-based microcomputer, released in 1978. More details about this simulation and the original machine are available in the C1Pjs Documentation.

[Embedded OSI Challenger C1P]

(If you see this message, C1Pjs may still be loading)

More Information

Learn more about the JavaScript Machines project and PCjs. To create your own PCjs machines, see the Documentation for details.

If you have questions or run into any problems, you're welcome to tweet or email.