ATAPI CD-ROM changer support is not properly supported in Windows 95 OEM Service Release versions 2, 2.1, and 2.5 (OSR2) when you are using a third-party ATAPI/IDE miniport driver.

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When you are using the ATAPI CD-ROM changer support in OSR2 with an ATAPI/IDE miniport driver, SRBs for MECHANICAL STATUS commands have no data buffers.

Atapchng.vxd does not set the IORF_CHAR_COMMAND or the SRB_DATA_IN flags when it translates MODE SENSE SRBs to MECHANICAL STATUS SRBs. This results in SCSIPORT not setting the data pointer in the SRB.

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A supported fix that corrects this problem is now available from Microsoft, but it has not been fully regression tested and should be applied only to systems experiencing this specific problem. If you are not severely affected by this specific problem, Microsoft recommends that you wait for the next service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web: The English version of this fix should have the following file attributes or later:

   Date       Time     Version     Size           File name
   -----------------------------------------------------------
   09/22/98   07:38p   4.00.1112   11,331 bytes   Atapchng.vxd
				

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Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article.

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This problem is known to occur with the VIA Technologies Bus Master IDE driver.

The third-party products discussed in this article are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.

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