COMxFIFO Does Not Properly Understand True and False (84873)


The information in this article applies to:

  • Microsoft Windows 3.1
  • Microsoft Windows 3.11
This article was previously published under Q84873

SYMPTOMS

The SYSTEM.INI [386Enh] setting COMxFIFO= does not correctly understand True/False, On/Off, or Yes/No. Using any non-numerical value sets the switch to "0" and therefore disables the FIFO.

CAUSE

The COMxFIFO= setting is not fully Boolean aware.

STATUS

Microsoft has confirmed this to be a problem in Windows version 3.1. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

WORKAROUND

Use the following settings: COMxFIFO=1 (On)

-or-

COMxFIFO=0 (Off)

MORE INFORMATION

This switch is used to enable or disable Windows 3.1 support for Windows-based applications using a COM port with a 16550 Universal Asynchronous Receiver Transmitter (UART). The 16550 has a 16-byte character FIFO buffer, or first-in, first-out buffer.

The SYSINI.WRI file from the Microsoft Windows Resource Kit (WRK) for version 3.1 incorrectly identifies TRUE/FALSE as functioning with this switch. Page 196 of the WRK guide incorrectly identifies On/Off as functioning with this switch.

For more information on this setting, query on:

COMMQ&A and windows 3.1

Modification Type:MajorLast Reviewed:10/14/2003
Keywords:KB84873
©2003 Microsoft Corporation. All rights reserved.