If, due to a hardware fault or program error, the computer fails to reset the watchdog, the timer will elapse and generate a timeout signal.
22.
The system then processes unhandled errors by looking in the registry for a " program error debugger " for which Dr . Watson is the default.
23.
The information obtained and logged by Dr . Watson is the information needed by technical support personnel to diagnose a program error for a computer running Windows.
24.
If the system does not find a program error handler, the system verifies that the program is not currently being debugged and considers the error to be unhandled.
25.
Thus a significant source of program errors can be detected early before software goes into production, and a more significant class of attacks on system security is not possible.
26.
Circular dependencies can cause a domino effect when a small local change in one module spreads into other modules and has unwanted global effects ( program errors, compile errors ).
27.
On the System / 36, a programmer could customize a menu using screen format language, but calling a customized menu that did not conform to exacting system requirements could cause a program error.
28.
On the System / 34, a clever programmer could customize a menu using screen format language, but, caution, calling a customized menu that does not conform to exacting system requirements can cause a program error.
29.
The engineers thought the mathematicians could compensate for this by programming arithmetic checks and the mathematicians would too readily assume that a wrong functioning was due to the machine when in fact it was due to a program error.
30.
Traps occur on some program errors, such as arithmetic overflow or an attempt to execute an undefined instruction; and also when the program executes an instruction such as BPT, EMT, IOT, or TRAP to request service from the operating system.
