Microsoft KB Archive/939536

= Read operations or write operations on a floppy disk may be faster when you use an earlier Microsoft operating system than when you use a newer Microsoft operating system =

Article ID: 939536

Article Last Modified on 11/26/2007

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APPLIES TO


 * Windows Vista Home Basic 64-bit Edition
 * Windows Vista Home Premium 64-bit Edition
 * Windows Vista Business 64-bit Edition
 * Windows Vista Enterprise 64-bit Edition
 * Windows Vista Ultimate 64-bit Edition
 * Windows Vista Starter
 * Windows Vista Home Basic
 * Windows Vista Home Premium
 * Windows Vista Business
 * Windows Vista Enterprise
 * Windows Vista Ultimate
 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional
 * Microsoft Windows XP Professional x64 Edition
 * Microsoft Windows Server 2003, Datacenter Edition for Itanium-Based Systems
 * Microsoft Windows Server 2003, Enterprise Edition for Itanium-based Systems
 * Microsoft Windows Server 2003, Datacenter x64 Edition
 * Microsoft Windows Server 2003, Enterprise x64 Edition
 * Microsoft Windows Server 2003, Standard x64 Edition
 * Microsoft Windows Server 2003, Datacenter Edition (32-bit x86)
 * Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)
 * Microsoft Windows Server 2003, Standard Edition (32-bit x86)
 * Microsoft Windows Server 2003, Web Edition
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Datacenter Server
 * Microsoft Windows 2000 Professional Edition
 * Microsoft Windows 2000 Server
 * Microsoft Windows NT 4.0
 * Microsoft Windows NT Advanced Server 3.1
 * Microsoft Windows NT Server 4.0 Standard Edition

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SYMPTOMS
Consider the following scenario. Read operations or write operations are performed on a floppy disk that is running on an early Microsoft operating system. Examples of early Microsoft operating systems include the following:
 * Microsoft Windows Millennium Edition
 * Microsoft Windows 98 Second Edition
 * Microsoft Windows 98
 * Microsoft Windows 95
 * Microsoft Windows 3.1
 * MS-DOS

These operations may be performed slightly faster on one of these early Microsoft operating systems than on a newer Microsoft operating system. Examples of newer Microsoft operating systems include the following:
 * Windows Vista
 * Microsoft Windows Server 2003
 * Microsoft Windows XP
 * Microsoft Windows 2000
 * Microsoft Windows NT

This behavior occurs if you use a floppy disk controller (FDC) that is 100-percent compatible with the original floppy disk controller. In a worst-case scenario, the difference in performance speed may be as much as 16 seconds.



CAUSE
This behavior may occur because the newer operating systems that are listed in the &quot;Symptoms&quot; section use a different algorithm from the algorithm that is used in the earlier operating systems. The newer algorithm is intended to speed up floppy disk access. However, this algorithm is not optimized for floppy disk controllers that are 100-percent compatible with the original floppy disk controller. When the newer algorithm is used with these controllers, the controller may wait for the read/write head to settle over the track after each movement of the head. Additionally, the controller may wait for a full revolution of the disk to occur after each movement of the head. Therefore, performance speed may be reduced.



MORE INFORMATION
For more information about a related issue, click the following article number to view the article in the Microsoft Knowledge Base:

159153 Error messages while backing up to some floppy disk drives

Keywords: kbprb kbexpertiseinter kbwinserv2003postsp2fix kbtshoot KB939536

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