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Files, Saving & Undo

Chip Hippo keeps your work in one ordinary file you can see, move, and share. This page covers what's in it, the four commands that manage it, the dirty marker, and undo/redo.

One file is the whole design

The desk in front of you is always a desktop of an open project, from the very first launch. A brand-new project has no name, no home of its own, and exactly one desktop called Desktop 1 — which is simply a desk to build on. See Projects & Desktops for keeping several desktops side by side.

The project is the document. A single .chiphippo file holds all of it:

Nothing else is needed to open a design. Copy that one file to another machine and it opens whole, ROM contents included — which is what makes a Chip Hippo design something you can actually send to someone.

Before you choose where it goes

Chip Hippo never stops you mid-thought to ask for a file name. A project that hasn't been given a home lives in a working slot inside the app's own data directory, and Cmd/Ctrl+S writes it there with no dialog at all. Design something, save, quit — it's there when you come back.

Save As… is what gives the project a real file, when you want one. From then on Save just writes that file. When you launch, Chip Hippo opens the unsaved project from its working slot if there is one; otherwise it reopens the project you used most recently.

New, Open, Save, Save As

Four commands — on the File menu, in the header toolbar's File pill, and under the usual shortcuts — manage the project's file:

If the file you pick already exists, your system's own save dialog asks whether to replace it, exactly as it does in any other app — Chip Hippo adds no second question of its own. Decline there and nothing is written.

File ▸ Project Properties… shows the project's Location alongside its Name and Description, without opening any dialog that writes.

Unsaved changes

The window title shows a • when the project has changes that aren't in its file yet: • 6502 SBC — Clock module — Chip Hippo. Save clears it. There is one marker because there is one document — it covers every desktop's design and the desktops themselves, so adding one, renaming one, or deleting one shows up there exactly as wiring a board does.

Nothing is written to your file until you save. Add a desktop, rename it, delete another — none of it touches your .chiphippo, and closing the project without saving takes all of it back. Tabs carry no marker of their own for the same reason: a desktop can't be saved on its own, so a dot on one would have nothing to clear it.

And nothing is lost to a crash either. About every 30 seconds, Chip Hippo tucks a copy of whatever you're working on into its own private folder — not into your file. So both things are true at once: the • still means "not in my file yet", closing without saving still takes it all back, and a power cut or a crash still costs you half a minute at worst.

If the app does go down unexpectedly, the next launch puts that work straight back on the desk and tells you so. It arrives unsaved — the • is showing — so you decide the same way you always would: save it, or close without saving to go back to what your file holds. A project you'd never saved anywhere is kept too; it was already living in that folder, and it still opens on its own.

You can ignore all of it. There's no setting, no prompt to answer, and nothing appears while you work. ⌘S is still what commits your work to your file, and still worth pressing when you want it there now.

Nothing that would lose your changes happens silently. Starting or opening another project asks first, and so does quitting. Both offer to save — and choosing that carries the action through, so you are never made to ask twice.

A project still in the working slot is asked about every time, even when nothing is unsaved: the incoming project is about to claim that slot, so there's nowhere for this one to stay. Save there means Save As — a file of its own.

When the save is the app's idea rather than yours — quitting with a • in the title — nothing is asked about where: the project goes to the file it already has, or to the working slot, where the next launch will find it.

Two things that are deliberately not counted as changes: which desktop is on the desk, and where the camera is. Moving between tabs and panning around never mark a design dirty.

Undo & redo

Cmd/Ctrl+Z undoes the last edit; Shift+Cmd/Ctrl+Z redoes it. Undo/redo covers the full editing history of the circuit — placing and moving boards, chips, and discretes; wiring and unwiring; deleting anything; net names — as far back as your session's history allows, and both menu items disable themselves automatically when there's nothing left to undo or redo.

Undo/redo is per desktop: switch away and back, and Cmd/Ctrl+Z still undoes that desk's last edit, not the other one's. Adding, deleting, renaming and importing a desktop are not on any undo stack — they're changes to the project's own structure, and what takes them back is closing the project without saving.

Undo/redo does not cover simulation state. While the circuit is running, editing — and with it, recording new undo steps — is locked, so nothing that happens mid-run (sequential chip state, clock phase, a chip taking 12 V damage) ever becomes an undo step of its own. All of it is run state: it exists while the circuit is running and not a moment longer.

That includes 12 V damage. Feed a chip 12 V and it lets its smoke out on the spot — the warning appears, its badge goes red, and it stays dead for the rest of that run, because a chip that's failed doesn't come back while the power is still wrong. Press Stop and every damaged chip is whole again. Wiring 12 V to the wrong rail is a mistake about the circuit, and a mistake you can see and fix; it was never meant to cost you the chip, so it doesn't. Fix the wiring, run again. What undo/redo restores is always the circuit you built, never a moment in its simulated behavior.

Example circuits

Chip Hippo's project repository ships a handful of ready-to-load example circuits as ordinary .chiphippo files — currently small W65C02-based breadboard computers built from 74xx glue logic, each paired with a .hex ROM image. Open one the same way as any saved design: File ▸ Open… loads it as a project of its own. Then load its matching .hex into the ROM chip via the memory inspector or the external programmer before pressing Run.

See Getting Started for building your first circuit from scratch, and Settings for what else persists between sessions.