Bomb (symbol)

The Bomb icon is a symbol designed by Susan Kare that was displayed inside the System Error alert box when the "classic" Macintosh operating system (pre-Mac OS X) had a crash in which the system decided it was unrecoverable. It was similar to a dialog box in Windows 9x that said "This program has performed an illegal operation and will now be shut down". But, since the "classic" Mac OS offered little memory protection, an application crash would sometimes take down the entire system.

The bomb symbol first appeared on the original Macintosh in 1984. Often, a reason for the crash including the error code was displayed in the dialog. If a person was lucky, a "Resume" button would be an option, which could be used to dismiss the dialog and force the offending program to quit, but most often the computer would have to be restarted. Originally, the resume button was unavailable unless the running program had provided the OS with code to allow recovery by passing a resume procedure to InitDialogs. With the advent of System 7, if the OS thought it could handle recovery, a normal error dialog box was displayed, and the application was forced to quit. That was helped by the classic Mac OS providing a little bit of protection against heap corruption using heap zones, if the application was to crash and the application's heap was corrupt, it could be thrown away.

The debugger program MacsBug was sometimes used even by end users to provide basic (though not always reliable) error recovery, and could be used for troubleshooting purposes much as the output of a Unix kernel panic or a Windows NT Blue Screen of Death could be. Mac OS Classic bomb boxes were often ridiculed for providing little or no useful information about the error; this was a conscious decision by the Macintosh team to eliminate any information that the end user could not make sense of.

In Mac OS X, the system architecture is vastly different from that in the classic Mac OS, and an application crash cannot bring down the entire system. A kernel panic screen (either text overwritten on the screen in older versions, or simplified to a reboot message in more recent versions) replaces the bomb symbol but appears less often due to the radically different system architecture. The bomb symbol is no longer used.

TOS-based systems, such as the Atari ST, also used bombs as the indication for an error. When a system error occurred, a row of bombs, variable in number, would show up on the screen and then disappear. A complete system crash resulted in the screen filled with bombs, which could not be removed without a hard reboot.

In the original Mac OS, the operating system call to display a "bomb box" was named DSError, and the corresponding alert table information was stored in resources of type 'DSAT'. "DS" stood for "Deep Shit", as in the "Deep Shit Manager." For documentation purposes, this was renamed the 'System Error Manager.' [ cite web|url=http://www.folklore.org/StoryView.py?project=Macintosh&story=Busy_Being_Born,_Part_2.txt |title=Busy Being Born, Part 2 |accessdate=2008-02-05 ]

References

External links

* [http://developer.apple.com/documentation/mac/OSUtilities/OSUtilities-29.html About the System Error Handler]

See also