16-Bit Apps Using NetWare Sharing Flag May Fail Using CSNW

• Microsoft Windows NT Server version 3.51
• Microsoft Windows NT Workstation version 3.51

SYMPTOMS

Shared access to a file on a NetWare server can fail with a sharing violation, even with the Shareable attribute set on the file at the NetWare server, when you use 16-bit applications that open the file for exclusive use.

CAUSE

Some older 16-bit MS-DOS-based applications that are not network aware tend to open files for exclusive use when in fact shared access to the file is desired. NetWare servers can work around this by setting a Shareable attribute on the file, which means that the server itself manages locking issues for the file and makes it shareable between multiple NetWare clients, even if a client application explicitly opens the file for exclusive use.

However, if a client specifies that the file should be opened with Deny Read and Deny Write access, then even with this Shareable attribute set, the NetWare server gives exclusive access to the file to that client. Sharing violations occur if other clients attempt to access the file.

In certain situations the 16-bit layer of the Client Services for NetWare (CSNW) redirector opens files with deny read and deny write access when the application really requires the file to be opened with exclusive access. This results in sharing violations, although the same operation succeeds using MS-DOS-based NetWare clients.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 3.51. A fix to this problem for 3.51 is in development, but has not been regression tested and may be destabilizing in production environments. Microsoft does not recommend implementing this fix at this time. Contact Microsoft Product Support Services for more information on the availability of this fix. This problem was corrected in Windows NT Workstation or Server version 4.0.