LowOS

LowOS is a browser-based operating system simulator built with HTML, CSS and JavaScript.

https://deddcode31251.github.io/LowOS/

• Virtual filesystem stored in browser localStorage (with a safe in-memory fallback)
• Desktop divided into four zones; drag desktop files between zones, or onto a folder to move them into it
• Right-click menu on the desktop and on icons (Open, Rename, Move to Trash, New File/Folder)
• Keyboard: Delete trashes the selected icon, F2 renames it, Enter opens it
• File Manager with sizes/dates, sorting, Copy / Cut / Paste (auto-renames on conflicts)
• Text Editor with unsaved-changes marker, Ctrl+S, Tab indentation, New, Save As, and Run ASM
• Calculator with a safe expression parser (no eval), keyboard input and backspace
• Browser with back/forward history and External mode (loads lazily, so startup never waits on the network)
• Trash Can with restore and permanent deletion (restoring never overwrites an existing file)
• CPU Lab: a real assembler/interpreter for a 4-register toy CPU with labels, comments and error messages with line numbers
• Shell with history, Tab completion, output redirection (>, >>) and many commands
• Backup / restore the whole filesystem as a JSON file (export / import)
• Draggable windows (mouse and touch), click-to-raise, double-click title bar to maximise
• Start menu (click LowOS in the top bar), toast notifications, responsive layout
• Fast boot: the desktop is ready before the boot animation finishes; click or press any key to skip it. Repeat visits boot in a fraction of a second.

index.html
style.css
script.js            window manager, desktop, menus, trash, terminal UI, boot
scripts/
├── filesystem.js    virtual filesystem + trash + backup
├── cpu.js           assembler and interpreter for the CPU lab
├── filemanager.js
├── texteditor.js
├── calculator.js
├── browser.js
└── terminal.js      shell commands, parsing and tab completion

Use a local web server because browser security is stricter when opening files directly.

python3 -m http.server 8000

Then open:

http://localhost:8000

help                       list commands
pwd | cd [path|-] | ls [-l] [path] | tree [path]
touch <file...> | mkdir [-p] <folder...>
cat <file...> | head/tail [-n N] <file> | wc <file> | stat <path>
write <file> <text>        overwrite (use \n for a newline)
append <file> <text>       append as a new line
rm <path...>               move to Trash
trash [list|empty] | empty | restore <trash-id-or-name>
rename <path> <new-name> | mv <src> <dst> | cp <src> <dst>
find [path] <name> | grep [-i] <text> <path...>
open <path> | edit <file>  (edit creates the file if it is missing)
files | calc | browser | lab | about
run <file.asm>             assemble and run a program
export | import | reset --yes
history | clear | date | echo <text> | whoami | uname | uptime | neofetch | reboot

Redirection works too: echo hello > a.txt, echo more >> a.txt. ~ means /home/dead.

Keys: Tab completes commands and paths, Up/Down browse history, Ctrl+L clears.

MOV r, x    ADD r, x    SUB r, x    MUL r, x    DIV r, x
INC r       DEC r       CMP a, b
JMP label   JZ label    JNZ label   JL label    JG label
OUT x       HLT         NOP

Registers are AX BX CX DX (32-bit signed). Operands are registers or numbers (10, -3, 0xFF). Arithmetic and CMP set the zero flag (ZF), so DEC CX / JNZ loop works as expected. Labels end with :, comments start with ;. Programs stop after 10 000 steps to catch infinite loops. Ctrl+Enter runs the program.

The filesystem is virtual. LowOS does not directly modify the real filesystem. Data is persisted with localStorage.

Default directories (these are protected and cannot be deleted, renamed or moved):

/
├── home/
│   └── dead/
│       ├── Desktop/
│       ├── Documents/
│       ├── Downloads/
│       ├── Pictures/
│       └── Projects/
├── system/
└── tmp/

If saved data is ever corrupted, LowOS starts from a fresh filesystem instead of failing to boot.

A normal web application cannot force every website to render inside an iframe. Sites can block iframe embedding with security headers. LowOS therefore provides an External button that opens the address in the user's normal browser.

Run reset --yes in the shell, or open browser developer tools and run:

localStorage.clear(); location.reload();

This resets the virtual filesystem and desktop state.