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Q110426: SMC 661-666 Floppy Controller, Errors Reading Disks

Article: Q110426
Product(s): Microsoft Windows NT
Version(s): 3.1
Operating System(s): 
Keyword(s): kbhw kbHardware
Last Modified: 08-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Server version 3.1 
- Microsoft Windows NT Workstation version 3.1 
- Microsoft Windows NT Advanced Server, version 3.1 
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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

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Keywords          : kbhw kbHardware 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW310 kbWinNTSsearch kbWinNTS310 kbWinNTAdvSerSearch kbWinNTAdvServ310 kbWinNTS310search kbWinNT310Search kbWinNTW310Search
Version           : 3.1

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