SMC 661-666 Floppy Controller, Errors Reading Disks

 Last reviewed: April 11, 1997
Article ID: Q110426

The information in this article applies to:
  • Microsoft Windows NT operating system version 3.1
  • Microsoft Windows NT Advanced Server version 3.1

SYMPTOMS

When you attempt to read from or write to a disk, one of several error messages appear; the most common is "invalid medium."

CAUSE

There is a problem in the SMC 661-666 series floppy controllers and their device drivers (FLOPPY.SYS).

NOTE: The following computer manufacturers are known to use these chips in some of their models: Compaq, Austin, and Gateway. This is not to say that the SMC chips with this problem are used in all models.

RESOLUTION

If you have an SMC floppy controller from the 663-666 range, the fix (see Status section below) should solve this problem immediately. For the 661 and 662 builds, you need to add a Registry value in addition to installing the fix to solve the problem:

NOTES:

  • On the SMC chip, there are a series of numbers (usually three lines of numbers). Which number or portion thereof identifies the SMC series.
  • Adding this Registry value may reduce floppy disk performance by as much as 40%.

WARNING: Using the Registry Editor incorrectly can cause serious, system- wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of the Registry Editor can be solved. Use this tool at your own risk.

In the following key, add a value called NotConfigurable, data type REG_DWORD, and value of 1: 

   SYSTEM\CurrentControlSet\Services\Floppy\Parameters
If you are experiencing this problem on a Gateway Pentium computer, you can download a fix from the Gateway BBS. For 2400 baud, call (605) 232-2109; for 9600 baud and higher, call (605) 232-2224.

STATUS

Microsoft has confirmed this to be a problem in Windows NT and Windows NT Advanced Server version 3.1. This problem has been corrected in the latest U.S. Service Pack for Windows NT and Windows NT Advanced Server version 3.1. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces): 

   S E R V P A C K
The products included here are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.

Additional query words: prodnt drive 4.0 4.00
Keywords : kbbug3.10 kbhw ntdriver nthw
Version : 3.1
Platform : WinNT

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Last reviewed: April 11, 1997
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