Hard Hoof OS

Implemented as a Java kernel + ROM userland (Hard Hoof OS 2.0; it was called VoltOS before 2.0). The pixel desktop is what the client shows for a powered Terminal, or a rack computer on a Console.

Hard Hoof OS boots when the Terminal has power and the front switch is on. The client never runs programs: it mirrors windows and sends input; the server owns processes, the file system, and drawing.

Boot

1. Power online → POST (HOOF BIOS 2.0, about 44 ticks): drive lines for rom0, flash0, bay media.
2. /rom/sys/init.volt runs. On a new computer it creates /home and seeds hello.volt and readme.txt.
3. Init launches Setup for a new computer, asking for its name, your login, and your company. On a configured computer with its lock enabled, it starts login instead. It also launches /startup.volt if you have created one. Init also starts remoted, the remote-access service (new in the development build; see The web & remote access).
4. RUNNING. Apps are scanned from /rom/apps, /apps, and each disk's /apps.

Power loss stops every process. Files on drives remain.

The screen

Element	Behavior
Resolution	480×270; dock 16 px at the bottom; window tabs 14 px
Desktop icons	Double-click to open an app. Right-click the desktop for more.
The Horn	Ctrl+Space, the goat at the bottom left, or just start typing on the desktop. Type part of an app, a command, an open window, a theme, or a sum (12*(3+4) shows 84; Enter copies it). Enter opens or runs the top match; Tab fills a name in.
Dock	Open windows; click to focus or restore
Window tab	Drag to move; the eye shows what the program is doing; minimize, maximize, close
Snapping	Drop a window on a side for half the screen, in a corner for a quarter, at the top for all of it. Ctrl+Alt+arrows do the same. Ctrl+Tab brings the next window up.
Esc	Closes the Horn or a menu first; then leaves the screen (the OS keeps running)
Drives drawer	Case button under the bezel: disks in bays 1-2, and the CPU, memory and network sockets
Toasts	sys.notify messages

At most 24 windows. The focused window gets keys and mouse.

The eye on each tab

Eye	The program is
Open, still	waiting for you (input)
Glancing side to side	working
Half shut	waiting on a device or a timer
Red	using its full instruction budget; inspect the program if the computer is busy

Themes

A theme sets every colour, the wallpaper, and the terminal's 16 colours. Shipped: Horn (the default), Paper, Phosphor, Amber, Blueprint, Alpine, Synth, Contrast.

• The Appearance app: pick a theme and the whole screen changes at once; Keep makes it stay after a restart, and closing without keeping puts the old one back.
• theme lists them; theme <name> wears one. The Horn finds them by name too.
• Your own: copy one from /rom/themes to /etc/themes and change it. Every running app repaints when the theme changes; /etc/theme remembers it across reboots.

App model

An app is a .volt file whose first line is:

// @app Display Name | icon

Location	Role
/rom/apps	Factory apps (read-only)
/apps on flash	Your apps
/disk/apps, /disk2/apps	Apps carried on removable media

Launch: a desktop icon, the Horn, the app's name at the shell, open, or proc.launch. Apps get their own process and window. See Apps.

Process model

• Compile cache by path + content.
• 500 kHz: 25,000 instructions a tick, shared round-robin. Input runs the receiving program at once, so typing echoes on the same tick.
• Natives may suspend (events, sleep, input, child exit, device call). Device calls answer next tick; at most 32 a tick; ABI v1 (see Data bus).
• The screen syncs per viewer, sending only what changed.

Weather and time

The desktop clock shows local solar time where the computer stands. Programs read the weather with sys.weather, sys.radar and sys.lightning, the sky with sys.sky, and the air and water round the computer with sys.env. The Weather and Sky apps and the weather command show them. These came with 0.6.0.

Running while you are away

Computers keep running when their chunk unloads, and a server restart resumes every program instead of rebooting. A single registry steps every Terminal, rack bay, Router and Exchange once a tick, loaded or not, and idle ones sleep until something happens. While unloaded:

• Files, drives and chips work on copies of what is in the slots, and the network works.
• A device in an unloaded chunk answers offline: <label> is not loaded. It stays listed.
• sys.sky and sys.env answer nothing; sys.survey and sound.note are refused.
• A drawing too big to save is saved blank, and the program is told to redraw when you return.

Power: in 0.6.0 an unloaded computer ran on its own charge (about 30 seconds idle for a Terminal). In the development build one on a factory's copper wire is fed by that wire as if you were there, and keeps running for as long as the wire has power. See Terminal.

The web and reaching it from outside

New in the development build. An Internet Dish gives a computer the real web through the Browser app, web and fetch. Every computer also has an Inter-Dimensional Address; /rom/sys/remoted.volt, started at every boot, lets Hard Hoof Studio log in with a code from remote pair. All of it is Volt that you can read and change. See The web & remote access.

Neural Link

With a Neural Link implant, J opens the last Terminal you used from anywhere in its world (see Terminal).

Not in yet

Topic	Reality
True GPU / 640×480	Planned hardware contract only; the framebuffer is 480×270 software windows
Volt-written kernel	Planned; today the kernel is Java