CPU-OS Simulator alternative: a CPU you build, in the browser
CPU-OS Simulator is free educational software from teach-sim.com that combines a CPU simulator with an operating system simulator, for teaching computer organization, architecture and operating systems. Its site describes it as integrated and multi-level, simulating several levels of hardware and software that support each other, and says it has been used in undergraduate modules at Edge Hill University, with research into its effectiveness funded by the Higher Education Academy. It includes a compiler and tutorials; the site notes the manual is still being prepared. The current version, 7.5.50, is a Windows program: the download is a zip whose installer has its extension renamed to .pkg for security, to be renamed back to .exe, and Linux and Mac users are pointed to Wine or a virtual machine. CPU-OS Simulator shows a modern CPU and an operating system working together; digiwleea has you build a small CPU yourself, gate by gate, in any browser.
What CPU-OS Simulator is good at
Seeing the software and hardware levels of a computer side by side: compile a program with its built-in compiler, run it on the simulated CPU and under the simulated operating system, in one integrated package designed for university modules on architecture and operating systems. (digiwleea is an independent project, not affiliated with CPU-OS Simulator or Edge Hill University.)
How digiwleea is different
digiwleea goes down instead of up: it runs in any modern browser with nothing to install, and you build the processor's hardware yourself. You start from CMOS transistors, make NOT and NAND, then adders, an ALU, registers, RAM, a program counter and a control unit, through a 40+ level course where every part is checked against its truth table, with an AI tutor (Wleea). The CPU you finish with is a small 8-bit accumulator machine whose capstone runs a stored LOAD, ADD, STORE, HALT program; there is no operating system. For a guided look at fetch, decode and execute in the browser, see the CPU simulator page.
| CPU-OS Simulator | digiwleea | |
|---|---|---|
| Focus | A CPU and an operating system, simulated together | Digital logic from transistors to a simple CPU |
| Runs on | Windows (Wine or a VM elsewhere) | Any modern browser |
| Install | Zip with a renamed installer (.pkg to .exe) | Nothing |
| The CPU | Given, with compiler and OS on top | Built by you, part by part |
| Price | Free | Free lab and Act I; Premium for the full course |
No sign-up is needed to start: open the lab and place your first transistor, or read the free theory course. The account (and the AI tutor) are optional.
More comparisons: CPU and assembly simulators
See for yourself: build a logic gate from transistors in the simulator, then follow the path from sand to an 8-bit CPU.
Open the digiwleea lab →Frequently asked
What is CPU-OS Simulator?
A free educational program from teach-sim.com that combines a CPU simulator and an operating system simulator, with a compiler and tutorials, for teaching computer architecture and operating systems.
Does CPU-OS Simulator run on Mac or Linux?
It is a Windows program. Its download page says it can run on Linux or Mac through Wine or virtualization software, preferably on a fast machine with plenty of memory.
Is there a CPU simulator that runs in the browser?
Yes. digiwleea runs in the browser: its CPU simulator page walks through fetch, decode and execute, and its course has you build an 8-bit CPU from transistors.