Explanation of Device Contention and Windows

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

SUMMARY

When more than one application is running at the same time in Microsoft Windows 386 enhanced mode, the applications sometimes request the use of a device such as a printer or a modem at the same time. The device contention options determine how Windows responds to these requests.

MORE INFORMATION

The device contention options apply only when a non-Windows application is one of the applications requesting access to the device. When more than one Windows application requests access to a device, Windows handles their use of the device without these options.

The device contention options are described in the following table. Generally, it is a good idea to accept the standard settings. Situations that might warrant changing the settings are included in the option descriptions.

Use This Option      To Do This
---------------      ----------

Always Warn          Specify that a warning message be displayed every
                     time an application tries to use the device when the
                     device is already in use. The warning message asks
                     you which application should be given control of the
                     port.

                     In most situations, you should select this option.

Never Warn           Specifies that any application can use the device at
                     any time, without a warning message. However, this
                     means that two applications could conceivably try to
                     use the same device at the same time; this may produce
                     undesirable results, such as a garbled printed
                     document.

                     Select this option when you are absolutely sure
                     that no more than one printing or communicating
                     application will try to use the device at the
                     same time.

Idle                 Specify the number of seconds after an application
                     stops using a device before another application can
                     use the same device without causing the warning
                     message to be displayed. The range is from 1 to 999
                     seconds.

                     Use this option when the device is capable of
                     switching back and forth between two applications.
                     For example, you might use Cardfile to automatically
                     dial an on-screen service and then switch to another
                     application to communicate with the service. In this
                     example, you would specify a short delay, such as two
                     seconds.

REFERENCES

"Microsoft Windows User's Guide," version 3.0, pages 190-192

"Microsoft Windows User's Guide," version 3.1, page 247