Windows Err Msg: Cannot Read From Device AUX...

• Microsoft Windows operating system versions 3.0, 3.0a, 3.1, 3.11

SYMPTOMS

When you use the debug version of Microsoft Windows version 3.0 or 3.1 without a debugging terminal, your system may stop responding (hang) for a time, then the following error message is displayed:

   Cannot read from device AUX: Retry/Cancel

CAUSE

The debug version of Windows is designed to wait for input from an auxiliary debugging terminal. If you don't have a debugging terminal attached to your system, the debug version of Windows cannot function as designed.

WORKAROUND

To prevent this error message, either connect a debugging terminal or reinstall the retail version of Windows.

To reinstall the retail version of Windows, do the following:

1. From the MS-DOS command prompt, change to the Windows directory.

2. In the Windows directory, type "D2N" (without the quotation marks) and press the ENTER key. D2N is a batch file that converts the debug version of Windows into the normal version.

MORE INFORMATION

The "debug" version of Windows is designed for the Windows Software Development Kit. This version reports errors more readily than the retail version of Windows. For example, bringing up the LaserJet III driver's setup screen causes an error to appear in the debug version of Windows, but does not generate an error in the retail version.

The error reporting mechanism used by the debug version of Windows is a "debug terminal." This is a dumb terminal connected to the computer's AUX: port. When Windows reports an error, it immediately sends information about the error to the debug terminal. After Windows displays the error information, it sends a prompt of "Abort, Break, Ignore?" to the terminal and waits for you to type an appropriate command (A, B, or I).

If no terminal is hooked up, or the terminal is turned off, the error codes are sent to a non-existent device. Also, you cannot type anything into the system keyboard while Windows waits for input from the debug terminal. After a period of time with no response from the terminal, Windows displays the "Cannot read device AUX" error box. Choosing Cancel causes Windows to exit, and choosing Retry causes Windows to wait until there is a response on the terminal. A Retry command can effectively lock your system if no debug terminal is connected.