About this Macintosh

The About this Macintosh is a feature from versions of classic Mac OS. The window shows the following information about the Macintosh:
 * Macintosh model (very specific until System 7.5)
 * RAM information, including:
 * Built-in RAM
 * Virtual memory, if used/supported
 * List of open application programs, including:
 * Name of applications
 * RAM usage, maximum allocated and actual amount in use
 * Version of the system software or Mac OS
 * Presence of any additional updates (such as the System 7 Tune-Up 1.1.1 or Mac OS 7.5.3 Revision 2.2)
 * Copyright information

Before System 7
While the easter egg policy was still relatively lax at Apple Computer, the names of four engineers (Larry, John, Steve and Bruce) sprang up on the About this Macintosh window.

System 7
With System 7, an icon to indicate the Mac model was added, and the window gained its 3D and color aspects on color Macs.

System / Mac OS 7.5.x
With the release of System 7.5, specific Macintosh model details were sacrificed, and a more general model description (e.g. "Power Macintosh", "PowerBook") was used.

Mac OS 7.6 to Mac OS 8.6
The menu command was altered to About This Computer... and the Mac model was no longer being displayed at all as of Mac OS 8. In its place stood a space-age picture with the words Mac OS computer.

Mac OS 9 to Mac OS 9.2.2
The version of the Mac OS was mentioned in two specific locations: first, the large image at the top of the window (general OS version), and the specific details below (e.g. if it was Mac OS 9.2, Mac OS 9.2.1 or Mac OS 9.2.2.

Mac OS X
With Mac OS X, the menu command was restored back to About This Mac. The era of Macintosh clones had come and gone, and no Mac clone could "officially" run Mac OS X.

The contents of the window grew. The version number and the build number were simultaneously visible until Mac OS X 10.1. As of Mac OS X 10.3.7, the window shows:
 * Apple logo
 * "Mac OS X" text
 * Text with current version; a click on that brings up the build number and the machine's
 * Memory and processor information
 * Buttons to open up Apple System Profiler and Software Update

Startup disk information was added with Mac OS X 10.4.

About the Macintosh Finder
System 6 used this interestingly-phrased menu command name before it was done with in System 7.

About This Macintosh
This was the official name for the whole series of operating systems from System 7 through to Mac OS 7.5.5.

About This Computer
This was the name of the menu commands under the following circumstances:


 * Macintosh Performas, as of System 7.0.1P and right up prior to System 7.5 while running Performa system software
 * All Macs as of Mac OS 7.6

About This Mac
Mac OS X restored a variant of "About this Macintosh..." to the Apple menu.