# Minimum system requirements

What Nomarchy expects of a machine. This is a **living floor**, not a
marketing sheet — numbers come from measured installs and known software
floors (Ghostty, NixOS, the ISO). When a real machine pushes a bound, update
this file in the same change.

Related: [HARDWARE.md](HARDWARE.md) (profiles/drivers),
[TESTING.md](TESTING.md) (ISO/VM), [README](../README.md) § install.

---

## Supported platform (hard)

| Requirement | Floor | Why |
|-------------|-------|-----|
| Architecture | **x86_64** | Only target the flake builds today |
| Firmware | **UEFI** | Installer uses systemd-boot; BIOS/legacy is LATER |
| Install path | Whole disk (disko) | No dual-boot / partial-disk path yet |

---

## Graphics (default desktop)

The default terminal is **Ghostty**, which requires **OpenGL 4.3** (desktop
profile). That is a **GPU generation** limit, not a “driver not installed”
problem:

| Generation (examples) | Typical max OpenGL (Mesa) | Default Ghostty |
|-----------------------|---------------------------|-----------------|
| Ivy Bridge / HD 4000 (e.g. **Acer Aspire M5-481T**, ~2012) | **4.2** | **Does not start** (`OpenGLOutdated`) |
| Haswell and newer Intel iGPU, most AMD GCN+, discrete GPUs of the last decade | ≥ 4.3 | OK |
| Dell XPS 9350 (Skylake) | ≥ 4.3 | OK (verified 2026-07) |

**Why 4.2 and not 4.3 on HD 4000?** The silicon and Mesa’s feature set for
that generation top out at OpenGL 4.2. No package upgrade on the distro can
turn Ivy Bridge into a 4.3 device. Ghostty is choosing a modern GL baseline
on purpose.

**Install-time fallback (shipped):** when `nomarchy-install` can probe OpenGL
(via `glxinfo` on the live session) and the version is **< 4.3**, it writes
`settings.terminal = "kitty"` into the machine’s `theme-state.json`. Kitty is
enabled and **themed from the same JSON** as Ghostty (palette, mono font,
opacity). SUPER+Return then launches Kitty. Ghostty stays installed (doctor /
calendar classed windows still call it — those helpers may still fail on old
GL until a later follow-up).

If the probe fails (no display / headless VM), Ghostty remains the default —
do not guess. Existing installs can set the same by hand:

```json
"settings": { "terminal": "kitty" }
```

then `nomarchy-home` (or `home-manager switch`).

Other Wayland clients vary; Hyprland itself is usually fine on these GPUs.

---

## CPU and memory

| Resource | Practical minimum | Comfortable |
|----------|-------------------|-------------|
| CPU | 64-bit x86_64, dual-core | Quad-core or better (rebuilds) |
| RAM | **8 GiB** | **16 GiB+** |

NixOS + Home Manager rebuilds and browser/Electron apps are memory-hungry.
Hibernation (default installer path) sizes a **swapfile ≈ RAM**, so low RAM
also means less disk eaten by swap — but also less headroom when building.

---

## Storage (the important one)

Nomarchy is a full NixOS desktop with:

1. **The Nix store** — every generation keeps package closures; updates add
   new paths until you GC. Many packages appear once per generation when
   inputs move.
2. **Home Manager generations** — desktop switches and `nomarchy-home` leave
   profiles behind until cleaned.
3. **BTRFS + snapper** — `@snapshots` timeline (hourly/daily) and
   pre-rebuild snaps. Excellent for recovery; **they retain data** and grow
   with how full the live filesystem is.
4. **Optional hibernation swapfile** — default size = **RAM** (e.g. 16 GiB
   RAM → 16 GiB swapfile on disk).

Closure size is **not** the same as disk use after hardlink optimisation
and is **not** the ISO size (see ROADMAP § chromium / #121 measurements).
Still, plan for **growth**, not for a single install footprint.

### Measured / known artifacts (order of magnitude)

| Artifact | Size (approx.) | Source |
|----------|----------------|--------|
| Offline live ISO | **~8.1 GiB** | Built image, 2026-07 (#103 era) |
| Template HM closure (nominal) | **~9.4 GiB** | `nix path-info` style figures in ROADMAP |
| Desktop store weight (uncompressed, pre-dedupe order) | **tens of GiB** | ISO pin / offline pin analysis (#120) |

A **fresh** install on empty disk is smaller than a machine that has been
updated and snapshotted for months.

### Recommended free disk (whole-disk install)

These are **planning floors** for the target SSD/HDD the installer will wipe
and use entirely — not “free space beside Windows.”

| Use | Capacity | Notes |
|-----|----------|--------|
| Absolute minimum to finish install + first boot | **≥ 40 GiB** | Tight; little room for GC delay or snapshots |
| Realistic daily driver | **≥ 64 GiB** | Short GC/snap retention still required |
| Comfortable (updates + snapper + apps) | **≥ 128 GiB** | Default recommendation |
| Power user / many generations / big apps | **256 GiB+** | Dev toolchains, Steam, local datasets |

**Plus swap:** if you keep hibernation (default), add **~RAM** on top of the
table (installer creates `/swap/swapfile` sized to RAM unless you set 0).

Example: 16 GiB RAM laptop → plan **≥ 128 GiB disk**, of which ~16 GiB is
swapfile, leaving room for store + snapshots.

### Why Nix “duplicates everything”

- Each **system** and **home** generation points at a closure of store
  paths. Unchanged paths are shared (same `/nix/store/…` hash); changed
  inputs pull **new** paths. After several updates you hold old + new until
  `nix-collect-garbage` / generation deletion.
- **Snapper** snapshots the BTRFS subvolumes. A snapshot is cheap until you
  rewrite a lot of data; then it retains the old blocks. Timeline + rebuild
  snaps mean “I deleted that 2 GB download” may not free space until snaps
  expire.
- The live **ISO** is large because it pins an offline install closure; that
  is a download/USB cost, not permanent free space on the installed machine
  after install (the installed system has its own store).

**Hygiene (user-facing, later doc links):** delete old generations, run GC,
tune snapper retention — see [RECOVERY.md](RECOVERY.md) and the System ›
Recovery menu. This requirements page only states why the disk fills up.

---

## What we explicitly do **not** require

| Non-requirement | Note |
|-----------------|------|
| NVIDIA as first-class | Deferred past v1 (PROPOSED); community/docs only |
| Secure Boot enrolled out of the box | Not the current install path |
| Touch / tablet as primary input | Untested as a bar |
| < 8 GiB RAM as a supported target | May boot; rebuilds and browsers will thrash |

---

## Machines that defined these bounds

| Machine | Role |
|---------|------|
| **Acer Aspire M5-481T** (~2012, Intel HD 4000, OpenGL 4.2) | Ghostty floor (#95); install bake / old-HW QA |
| **Dell XPS 9350** (Skylake) | Install bake (#123); Ghostty OK |
| AMD dev box / Latitude / T14s | Ongoing V3 (HARDWARE-QUEUE) |

When you install on something older or smaller than the table, file what
broke in `agent/BACKLOG.md` and tighten this page.

---

## Related work

| Item | Topic |
|------|--------|
| BACKLOG **#95** | Ghostty fallback when OpenGL < 4.3 |
| BACKLOG **#120** | Lighter netinstall ISO (download size ≠ installed size) |
| BACKLOG **#123** | Installer HM pre-activate (first-boot polish) |
| BACKLOG **#124** | Flake pin vs main/v1 lag after install |