Crash TestTM 1.0b5

June 20, 2000

Crash Test lets you test the capabilities of crash recovery tools by purposely causing a variety of different Mac system crashes.

NOTE: Crash Test works by causing REAL crashes. In most cases, the only way to recover from these crashes will be to restart, and any unsaved work will be lost forever. DO NOT run this application while doing normal work on your computer.

Some crash utilities force all other applications to quit before crashing. While this gives you a second chance to save your work, it disables some crash recovery tools themselves, including Kick-off!, Rebound!, and PowerKey Pro with Server Rebound Option (SRO), and causes the test to lose its "real world" validity.

How Crash Test Works

Following is a technical discussion of the types of crashes caused by Crash Test.

Freeze System

This test freezes the entire system by disabling interrupts and going into an "infinite loop". This type of crash typically happens when low-level tasks (such as some extensions) fail to return control to the system. When this happens, even the most basic system tasks (e.g., moving the mouse) fail.

Since all activity stops, most hardware-based recovery tools will usually detect this type of crash, but most software-based recovery tools cannot operate.

System Error

This test attempts to execute a low-level system routine (a "trap") that has not been defined. This generates a "system error". The Mac generates system errors in many cases where it is simply unable to continue, such as when trying to execute invalid code, accessing memory that isn't there, or running out of application memory.

Newer versions of the Mac OS will attempt to recover from some system errors by quitting the offending application. This results in an "application has unexpectedly quit" message being displayed. If that is not possible, the familiar "sorry, a serious system error has occurred" message appears, and the only choice is to restart.

In the case of a "serious system error" message, all but the lowest-level activity will stop, so hardware-based recovery tools will usually detect this type of crash. Additionally, because some low-level tasks are still operating, some software-based tools will also detect this crash.

In the case of an "unexpectedly quit" message, most background activity will continue, so recovery tools with only system-level detection will often miss this type of crash.

Hang Application

This test freezes the system by going into an "infinite loop". This differs from the "Freeze System" test in that it causes other applications to stop, but most low-level tasks (e.g. moving the mouse, updating the menu bar clock) and some extensions will continue.

Because low-level tasks continue, hardware- and software-based tools which operate as low-level tasks can miss this type of crash. But Kick-off! and Rebound! operate as background applications, so they will detect this crash.

Application Timer Expire

This test tickles an "application timer" in Kick-off!, Rebound! and PowerKey Pro with SRO, setting it to a value of 10 seconds, then never updating it. This simulates a directly-supported application which doesn't crash completely, but fails to respond due to an internal error.

An application with direct support for our Rebound! technology normally tickles its AppTimer every minute, so it will never reach zero. If the AppTimer does reach zero, it means that something has gone wrong with the application, so our product can respond.

Beta Version

* 1.0b5 - First release.

How to reach us

Sophisticated Circuits, Inc.
PO Box 727
Bothell, WA 98041-0727

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phone: 425-485-7979
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Copyright ©2001 Sophisticated Circuits, Inc. All rights reserved.
The files in this package may not be redistributed in any way without express permission from Sophisticated Circuits, Inc. PowerKey and Rebound! are registered trademarks, and Kick-off! is a trademark of Sophisticated Circuits, Inc. All other products mentioned are trademarks of their respective owners.