Rustaman

A modern Windows task manager.

The one that ships with Windows is slow to open, freezes exactly when the machine is busy, and looks like it was designed in 2012 because it was. Rustaman is a native Rust rewrite of the idea: the same data, read through the same interfaces, in a window that stays responsive when the machine does not.

The Performance view, rendered by the repository's offscreen screenshot harness.

• Periodic monitoring stays off the UI thread. A background sampler overwrites a latest-value mailbox; the window draws the freshest snapshot. Explicit user actions remain synchronous so their result is immediate.
• One NtQuerySystemInformation call gets CPU, memory and I/O for every process at once, instead of the ~2,500 syscalls per second the documented route costs — and unlike that route, it can see protected system processes.
• Eight themes, or write your own. A theme is thirteen colours in a TOML file. Everything else is derived, and every theme is checked against WCAG contrast as a build step.
• Rainbow accents that mean something. Per-core graphs, chart series and category chips all index one perceptually-even OKLCh ramp, so no series looks more important than its neighbours.

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What it does

View
Processes	A real tree, grouped into Apps / Background / Windows. Collapsed parents carry their subtree's totals, so a browser's thirty renderers do not hide behind it. Cells are heat-tinted by load, so a glance down a column finds the heavy rows.
Performance	CPU (total, kernel band, labeled logical-processor grid, and recent averages/peaks), memory and commit pressure including kernel pools, per-disk active time and throughput, network link/totals, and GPU engines and dedicated memory.
Memory	A per-process treemap showing what is holding physical memory and how each selected process is using it.
Details	One flat technical table plus an inspector: owner, session, bitness, elevation, handles, threads, cumulative I/O, full path.
Services	Every Win32 service with its state and hosting PID, and "go to process" to jump from svchost.exe to whichever of its fifteen services is busy.
Startup	Canonical user/machine Run and RunOnce registry views plus both Startup folders, including Task Manager approval state.
System	Windows edition/build, computer model, firmware, processor, memory, storage, graphics, network hardware, and live machine totals.

Actions: end task, end process tree best-effort from the current snapshot (children first), suspend, resume, priority, open file location, copy details, start/stop a service.

Search

The box takes plain text, or field:value terms combined with AND:

chrome                    anything matching "chrome"
pid:4242                  by process id
user:system               owned by SYSTEM — unambiguously
-chrome user:alice        alice's processes, excluding chrome
"visual studio"           a phrase

Keyboard

Delete	End the selected task
F5	Re-read services and startup entries
Ctrl+F	Search
Esc	Clear the search, then the selection
Ctrl+1…8	Switch view

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Requirements

Windows 10 1809 (build 17763) or later, 64-bit. Nothing newer is assumed — every API past that floor is probed at runtime, so a missing counter costs a column rather than the app.

It runs unelevated. The process list, the graphs, the services and the startup entries all work without administrator. Running as administrator adds SeDebugPrivilege, which fills in the owner, path and architecture columns for processes belonging to other accounts; the Settings view says which mode you are in.

Building

cargo build --release

The toolchain is pinned in rust-toolchain.toml, so rustup fetches the right one automatically.

cargo test                                        # the test suite
cargo clippy --all-targets --all-features -- -D warnings
cargo fmt --all -- --check
cargo run --example brand_assets                  # regenerate assets/brand/

The portable half of the crate — the model, the theming, the formatting, the rate arithmetic — builds and tests on any platform:

cargo test --lib          # on Linux or macOS: the portable model and utilities

Theming

Drop a .toml file into %APPDATA%\rustaman\themes\:

[[theme]]
id = "my-theme"           # never rename one; it is what gets persisted
name = "My Theme"
mode = "dark"             # decides which way the surface ramp runs

app = "#0a0c11"           # behind everything
panel = "#11141c"         # a panel on it
raised = "#1a1e28"        # a card or row on that
hover = "#242936"         # the interactive lift

border = "#333a4a"
accent = "#4cc9f0"        # also the centre of the rainbow ramp
text = "#e9edf5"
text_muted = "#98a3b8"
danger = "#ff5c7a"
warning = "#ffb347"
success = "#4ade80"

rainbow_span = 280        # optional: degrees of hue the ramp covers

That is the whole format. The selection fill, the scrollbar handle, the grid lines, the text colour that goes on the accent and the entire series ramp are all derived — which is what stops a new theme from shipping a scrollbar the same colour as the card it scrolls.

Give a user theme the same id as a built-in one to replace it. The Settings view previews each theme's surfaces, accent and ramp, and reports any that failed to load.

Configuration

%APPDATA%\rustaman\config.toml, written on exit. Every field is optional and parsed independently — one bad value costs that setting, not the file. rustaman --reset starts from the defaults if a saved setting has made the window unusable.

What it deliberately does not do

• Per-process network throughput. No Win32 call provides it; Task Manager reads an ETW kernel session, which means a continuous trace and the privileges one needs. Rustaman shows open TCP/UDP endpoint counts instead — cheap, IPv4+IPv6 aware, and unprivileged.
• Enable or disable startup entries. It reports what is registered and whether it is enabled. Toggling one means writing another program's registry state, which is not something to add without a flow designed around it.
• Send anything anywhere. There is no network code in this app beyond reading local adapter counters.

docs/WINDOWS_APIS.md records which API answers which question, what each costs, and what none of them can tell you.

Documentation

• docs/ARCHITECTURE.md — the module map and the layering rule
• docs/WINDOWS_APIS.md — every Windows interface used, and why
• docs/PERFORMANCE.md — read before touching a per-frame path
• CONTRIBUTING.md — how to build, test, and what CI enforces
• CLAUDE.md — the rules this codebase actually enforces
• CHANGELOG.md — generated from the git history, never hand-edited
• SECURITY.md — how to report a vulnerability privately

Licence

MIT. See LICENSE.