The bench — MUI

Why any of this

The Amiga 1200 was the last great Amiga Commodore made, and the desktop people built on it is the one worth having back: Kickstart 3.1, AGA, a hard disk, a graphics card for a screen bigger than the chipset could draw, MUI for modern windows, color icons, and WHDLoad so every game lives on the disk instead of in a box of floppies. An emulator or a MiSTer puts that machine back on your desk. Getting to that finished desktop is the work.

You cannot download it ready-made. Workbench and Kickstart still belong to someone, so the disks and the ROM have to be yours, and Commodore’s own installer has to copy them. Everything after that is a recipe of Proceed buttons, the Green Amiga Alien guide, which people have followed by hand for twenty years. These notes turn that recipe into scripts, so someone new to Amiga emulation gets the upgraded A1200 in an afternoon, from disks they own.

The end of the road is a build nobody babysits. AmiPilot can sit inside the running Amiga, click what is left of the installers, and take a picture of the screen, so an AI agent can check that the desktop came up, that the icons are in color, that a game launches, and fix the script when they are not. Every page here is one step toward that.

Open any window on a stock Workbench 3.1 and try to make it wider. The buttons stay where they were drawn. Change the system font and half of them overlap. Amiga programs of the time laid their controls out in pixels, on the assumption of a 640-wide screen and Topaz 8, because the operating system gave programmers almost nothing else: GadTools, a thin library from Kickstart 2.0 that placed a button where you told it and did no arithmetic on your behalf.

In 1992 Stefan Stuntz started building the arithmetic. MUI, the Magic User Interface, describes a window as a tree of objects, groups inside groups, and works out where everything goes at the moment the window opens, for whatever font, screen and size it finds itself on. Version 1.0 went out in August 1993. By 1996 Amiga Computing was calling it the most popular Amiga shareware ever, and the programs that defined the late Amiga, the web browsers, the mail clients, the file managers, drew their windows with it. It never stopped: it is the native toolkit of MorphOS today, and AROS reimplemented it as Zune.

The user, not the programmer, decides what the windows look like. That is the whole idea, and it is why there is a preferences program.

Every MUI program reads one set of settings, and the settings belong to you. Frames, background patterns, fonts, the shape of the scrollbars, how a list highlights, whether windows remember their positions: all of it lives in MUI Preferences and applies to every MUI program at once. Stuntz shipped his own taste as a preset, Stuntzi.prefs, and loading it is the first thing every guide tells you to do. MUI was shareware, and stayed shareware: unregistered, everything works, but the preferences program lets you change only some of it. Version 3.8, from February 1997, was the last release of the classic era, the one every guide installs, and it is the one on this disk.

The Prefs drawer with MUI and PSI icons among the Workbench preference editors. — After the install. MUI and PSI, the Public Screen Inspector that comes with it, sit in the Prefs drawer beside Commodore’s editors. Captured on the MiSTer.

A Scalos window on the MiSTer showing the Ram Disk and WHDLoad icons. — The reason it is here. Scalos runs without MUI but every one of its preferences windows is an MUI program.

What it is on this disk

Installing MUI copies one drawer, SYS:MUI, with the libraries, the classes, the preferences program, and the presets, then adds a line to S:User-Startup so that MUI: points at it on every boot. The install script in the archive spends a dozen Proceed buttons asking whether you want the demos and the documentation and where to put them. On this disk the answer is the same every time: the drawer goes on the system partition, the demos stay out, the preferences programs go into Prefs so they sit next to Commodore’s. That is the whole install, and it is why it was the first thing to script.

One click remains, and it is a real one. Loading a preset and saving it writes the settings file MUI actually reads, and MUI Preferences is itself an MUI program. That matters for the automation more than it should. AmiPilot finds buttons by walking the Intuition gadget list of a window, and an MUI window has, from Intuition’s point of view, a handful of system gadgets and one large custom gadget with everything painted inside it. Save, Use, Test, Cancel: none of them exist to the tree walker. What does exist is the menu strip, because MUI builds a real Intuition menu, and AmiPilot picks menu items by position. Project, Quit closes the window from a script; Project, Open brings up an ASL requester whose buttons are ordinary gadgets. So the window in the picture was opened, captured and closed without a hand on the mouse. The preset is still loaded by hand, because the Save at the end of that path is a painted MUI button; the ledger row below says so.

The MUI Preferences window, Info page: the unregistered notice, the page list on the left, Save, Use, Test and Cancel along the bottom. — MUI Preferences on the WinUAE acceptance disk, opened by capture_prefs.sh and closed by it through Project, Quit. The unregistered notice is the shareware model in one paragraph: the settings pages are there, most of them disabled until a keyfile arrives.

What the scripts and AmiPilot took over

Chapter 6 of the guide is MUI. The steps, and where each of them went.

Automated
Fetch
Download mui38usr.lha into Programs.
fetch_archives.sh pulls it from Aminet. The Programs folder on the Amiga side is gone; the archive stays on the host.
Eliminated
Boot, Shell
Reload WinUAE, open a Shell, lha x the archive, endcli.
7z unpacks it on the host. The Amiga is not running while this happens.
Automated
Install-MUI
Intermediate User, install onto the system partition, no demos, a dozen Proceeds.
install_mui.sh copies the drawer to SYS:MUI, the preferences programs to Prefs, and appends the MUI: assign to S:User-Startup. Stuntzi.prefs lands in MUI:Presets. Demos are left out unless you ask. The same script runs inside setup_winuae.sh --mui and build_mister_image.sh, so both targets get the identical drawer.
Once
Reset
Ctrl-Amiga-Amiga.
The first boot of the new disk. The assign runs from User-Startup and MUI programs work from then on.
By hand
Preset
Open MUI in Prefs, Project, Open, Stuntzi.prefs, Save.
Still those menus, though less of them than before. AmiPilot can open the window, pick Project, Open, dismiss the requester that brings up, and quit again; it cannot press Save, which is a painted MUI gadget rather than an Intuition one. The saved settings file has not been vendored the way the palettes were. The one remaining click on the MUI path.
Automated
Check
Open a MUI program and see if it comes up.
check_guide_hdf.sh confirms the library, the drawer and the assign line on the finished hardfile. install_scalos.sh refuses to run until MUI is there, because Scalos’s preferences would not open without it.

Steps follow Chapter 6 of the Green Amiga Alien guide; the ledger for it is here. History from the MUI history file and Stuntz’s MUI 3 documentation. The words are ours.