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Q149564: Poor Performance Reading Video CD in IDE CD-ROM Drive

Article: Q149564
Product(s): Microsoft Windows 95.x Retail Product
Version(s): WINDOWS:95
Operating System(s): 
Keyword(s): kbfile diskmem win95 kbgraphxlinkcritical kbDiskMemory
Last Modified: 21-DEC-2001

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The information in this article applies to:

- Microsoft Windows 95 
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SYMPTOMS
========

Data transfer can occur very slowly when you are reading a video CD in an IDE
CD-ROM drive if the following conditions are true:

- The IDE CD-ROM drive is configured as the slave device on an IDE channel,
  with another device (such as a hard disk) configured as the master device on
  the chain.

- You are using protected-mode drivers to access the IDE devices, including the
  CD-ROM drive.

For example, playing an MPEG file from a video CD can cause the computer to seem
to stop responding (hang) due to the very slow rate at which data is being read
from the CD.

CAUSE
=====

There is a problem in the Ios.vxd file that causes excessive seeks on data
requests from the CD-ROM drive under these conditions. This results in
degradation in the rate of data transfer from the drive.

RESOLUTION
==========

Microsoft has released an updated version of the Ios.vxd file that corrects this
problem. The file is:

  IOS.VXD version 4.00.953 (3/19/96, 68,825 bytes) and later

To install the updated Ios.vxd file, follow these steps:

1. Download the IOSUPD.EXE file from one of the online services listed below to
  an empty folder.

2. In My Computer or Windows Explorer, double-click the IOSUPD.EXE file you
  downloaded in step 1.

3. Follow the instructions on your screen.

The following file is available for download from the Microsoft Download Center:

  Download Iosupd.exe now

For additional information about how to download Microsoft Support files, click
the article number below to view the article in the Microsoft Knowledge Base:

  Q119591 How to Obtain Microsoft Support Files from Online Services

Microsoft used the most current virus detection software available on the date of
posting to scan this file for viruses. Once posted, the file is housed on secure
servers that prevent any unauthorized changes to the file.

MORE INFORMATION
================


For information about other issues resolved by this update, please see the
following article in the Microsoft Knowledge Base:

  Q149563 Fatal Exception 0E in IOS.VXD with SCSI Printer


Additional query words:

======================================================================
Keywords          : kbfile diskmem win95 kbgraphxlinkcritical kbDiskMemory 
Technology        : kbWin95search kbZNotKeyword3
Version           : WINDOWS:95

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