TempleOS: A Non-POSIX Operating System That Removed Protection on Purpose

Source: Dev.to

What This Operating System Is

TempleOS is a standalone 64‑bit desktop operating system written almost entirely by one person.

It includes:

• its own kernel
• its own programming language (HolyC)
• a graphical desktop
• native applications
• its own build tools

There is no external userland, no third‑party libraries, and everything runs inside one unified system. TempleOS is not a fork, distribution, or compatibility layer.

Why TempleOS Exists

Most operating systems grow complex because they try to support multiple users, hostile programs, networks, and long‑running services. TempleOS exists because its creator wanted the opposite:

• a single‑user system
• complete control
• immediate execution
• zero abstraction between code and hardware

The design goal was clarity and immediacy, not safety or scalability. In TempleOS, the system does exactly what the code says—nothing more, nothing less.

Kernel

TempleOS uses a monolithic kernel with no separation between kernel mode and user mode.

Key characteristics:

• single address space
• no process isolation
• no virtual memory protection
• no preemptive multitasking

All code runs at the highest privilege level, making the system extremely simple, fast, and fragile. The kernel trusts the programmer completely and provides no defensive mechanisms.

POSIX Status

TempleOS is explicitly non‑POSIX. It does not implement:

• POSIX system calls
• Unix process model (fork/exec)
• signals
• permissions
• file descriptors

There is no attempt at Unix compatibility. While POSIX assumes multi‑user systems, unsafe programs, and defensive kernels, TempleOS assumes a single trusted user, a single trusted program, and no hostile environment.

Programming Model

TempleOS introduces HolyC, a language similar to C but tightly integrated with the OS.

Characteristics:

• direct hardware access
• no separation of standard library
• code can modify the kernel at runtime
• immediate compilation and execution

There is no distinction between “application code” and “system code”; programming in TempleOS means programming the entire machine.

Processor Architecture

TempleOS targets x86‑64 only and assumes:

• legacy BIOS boot
• a stable CPU environment
• no need for portability

Support for other architectures was never intended. The OS is tightly bound to the hardware to keep the system small and predictable.

File System

TempleOS uses its own simple custom filesystem with the following traits:

• flat and minimal structure
• no permissions
• no journaling
• direct access

The filesystem exists solely to load and save code; data safety is the responsibility of the user, not the OS.

Hardware Requirements

TempleOS has very modest requirements:

• CPU: x86‑64 processor
• RAM: very low by modern standards
• Storage: small disk footprint
• Graphics: fixed low‑resolution mode

It runs best on virtual machines or older PCs and is not designed for modern GPUs or peripherals.

Who Should Use TempleOS

TempleOS makes sense for people who:

• study operating system fundamentals
• want to understand life without protection layers
• explore extreme simplicity in system design
• are interested in OS history and philosophy

It is useful as:

• a conceptual reference
• an educational artifact
• a demonstration of design trade‑offs

Where TempleOS Does Not Make Sense

TempleOS is not suitable for:

• networking
• multi‑user systems
• security‑critical environments
• modern desktop workflows
• production use of any kind

It deliberately ignores almost everything modern OSs try to solve. TempleOS matters not because it is practical, but because it is honest—it shows what an operating system looks like when protection, compatibility, and scalability are removed entirely, reminding us why modern safety features exist.