Happy Mac

A Happy Mac is the normal boot up icon displayed by Macintosh models running older versions of Mac OS or Mac OS X from Apple Computer. It was replaced by a large grey Apple logo with the introduction of Mac OS X 10.2.

Classic process
When a Macintosh computer is booted, it makes a startup beep or chime as the ROM is loaded. No sound will indicate an electrical or mechanical problem.

After the ROM is loaded and diagnostics are completed, the screen will turn gray as the computer looks for a bootable operating system. If the diagnostics fail, a Sad Mac icon will appear instead, indicating a problem in the boot sequence.

If the computer cannot immediately locate a bootable system file (whether from an internal hard drive or floppy disk), a blinking floppy (or folder) icon with a question mark will be displayed until such a disk is inserted or mounted.

Once a bootable system file is found, a Happy Mac icon will appear, followed by the welcome or startup screen of the version of Mac OS that is being loaded. In classic Mac OS, icons of loaded extensions and control panels may be displayed at the bottom. After the system has completed loading, the Finder will normally be launched by default and the desktop will appear.

Icon types
On most Old World ROM Macs, the Happy Mac image is a monochrome icon stored in the Macintosh Toolbox ROM. A monochrome floppy icon with question mark is also stored in there for when the system file cannot be found. In early Open Firmware Macs (OF version 1.0.5 to 2.0), which were still considered "Old World", the monochrome icon and Toolbox were stored within an OF device within the ROMs.

The first Macs to display color or grayscale Happy Mac icons during startup were the PowerBook Duo 2300c and PowerBook 5300 series, released in August 1995. The first desktop model was the Power Macintosh 4400, released in November 1996 and based on the Tanzania architecture (OF version 2.0.2), also used by Macintosh clones. On New World ROM Macs, the color Happy Mac icon is stored in the Mac OS ROM file on the boot drive. Starting with Mac OS X 10.2, this is bypassed and a plain gray Apple logo is displayed instead. A color folder icon with question mark is stored in Open Firmware for when the system file cannot be found.

On Intel-based Macs, the plain monochrome icons were stored in the EFI firmware.

Articles

 * Changing Your Startup Drive by Dan Knight at Low End Mac (1998-03, updated 2001-12)
 * Remember starting up to a Happy Mac? by Christopher Phin at Macworld (2015-11-24)