Measuring the time it takes to complete a process and using that for the progress bar on the next run seems like the opposite of faking it to me.

Calling it fake also doesn't mean I'm calling it poor engineering; in fact the opposite since it's very accurate for the common use case of a computer that's used on a day-to-day basis with no major hardware or software changes. It's fake in the same way that illusion magic like slight of hand is fake. Its not lying to anyone about what it is, because it prompts your senses in a particular way that causes your brain to lie to itself! The slight of hand is this:

- Observable fact: Taking the computer from a fully-powered-off state to a usable state happens when the user presses the power button, involves loading the operating system from slower disk to faster memory, and takes some amount of time to complete.

- Observable fact: `WaitForLoginWindow` is the first “Aqua” UI element one sees after powering their computer on, the first visible thing that's drawn by the operating system that's being loaded instead of drawn by OpenFirmware or by BootX.

- Observable fact: Aqua has an `NSTabView` control used for grouping panes of related UI elements. In original 2001 Aqua, NSTabView looked like something that “stuck out” toward the user from a window. In Panther (2003) it was redesigned into something that looks “sunken in” to visually allow for nesting multiple layers of grouping.

- Observable fact: Panther-style NSTabViews get progressively darker as they are nested, indicating controls which are “more related”. See here for an example of four layers of nested NSTabView: https://cdn.arstechnica.net/wp-content/uploads/archive/mac-o...

- Observable fact: Any OS X user will be familiar with `NSProgressIndicator` as the UI control they see when they tell their computer to do something and some aspect of the computer itself (like disk or network bandwidth) is the limiting factor causing their action to be non-instantaneous.

- Observable fact: The progress indicator is the only part of `WaitForLoginWindow` that moves, and it's grouped with a text label reading “Starting Mac OS X…” in what looks to be a `noTabsBezelBorder`-styled `NSTabView` even though the grouping-box and even the “Starting” text are actually just a static image that the Wait window draws and overlays the progress indicator on, not really Aqua controls because the UI frameworks are still being loaded.

- Illusion magic: Look at the Tiger boot screen, compare it to the previous link, and notice how the fake grouping pane is as dark as what four nested levels of real NSTabViews would be: https://cdn.arstechnica.net/wp-content/uploads/archive/journ...

The coloration makes your own brain tell you that the progress indicator and the “Starting Mac OS X” text are as related as any two UI elements could possibly be, more related than any other pair of UI elements you will ever encounter in Mac OS X, because no reasonable application designer would ever nest four layers of NSTabView.

Since the progress indicator is so strongly visually grouped with the “Starting Mac OS X” text, and every Macintosh going back to 1984 has displayed some form of “Welcome to Macintosh” text while the OS is loading from disk, and progress indicators are the UI element for long-duration user-initiated work, and the computer was fully off so pushing the power button was the only thing the user did, and the wording of “Starting” means it isn't fully “Started”, then the progress indicator must represent how much of the OS is loaded in the current session, right?