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HP OpenVMS Systemsask the wizard |
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The Question is: We are developing a VB application (on Windows 95) accessing a RDB database on a VAX. The existing system calls a system routine $ENQ to perform record locking. We need to duplicate that logic in the VB application. Any suggestions? The Answer is : The sys$enq call is the OpenVMS system service that enqueues a lock request (on an arbitrary, pre-arraigned resource) to the OpenVMS distributed lock manager (DLM). The DLM is used to synchronize application access to arbitrary constructs and as an interprocess communications mechanism among cooperating applications. The DLM can assist applications in controlling the ownership and access to bits in memory, the selection of a single primary application process with multiple secondary backup processes across all nodes within a cluster, interprocess communications via the lock value block, an interprocess notification of a change made to a global section, and the application that various folks have assumed is the only use for the lock manager, the file system. Many other uses are also possible. Please ask a Microsoft Wizard for information and assistance on locking primitives and/or for the implementation of a distributed lock manager for Windows 95 and/or Windows NT. Application programming suggestions for Windows 95 and Windows NT systems are well outside the realm of questions for the OpenVMS Wizard.
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