The VME does not contain application files. User data is located outside the VME, stored on the D3 Windows file system distributed across the network. Data is accessed through the Open Systems File Interface (OSFI), which provides transparent access to D3 applications, and allows sharing data with Visual Basic applications or other VME environments on the network.
The driver name in the dm,hosts, file is FSI.
Files located outside the VME are managed by the D3 File Manager. There are several advantages to locating files outside of the VME:
Data is shared with other applications or with other VME environments, allowing VME users access to several systems.
Data is distributed. Accounts and files are read from many servers, improving performance and reliability.
Better multiuser performance. Each file object manages its own locking and disk space, limiting the bottlenecks on shared resources.
Disk space is used more efficiently. The VME can be left to a very small size, since it needs to handle only spool jobs, user workspace, and some small required files in the dm account.
The File system is more reliable. Because files are distinct objects on the network, locks and disk space are handled independently of other files, limiting risks.
Unlimited file size (2 terabytes per file), as opposed to the current 1 GB for the entire VME.
Note that accessing files from the network is slower than with files located inside the VME.
Once an account has been restored into the external file system, log to the external account by creating a Q-pointer in the MDS. For example, to create a Q-pointer to the external account accounting, create the following item in the MDS:
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accounting 001 Q{S} 002 fsi:accounting |
The QS.UPD utility creates all Q-pointers automatically.
To access databases or tables defined in another Network Domain, use Table Naming Conventions as described in the Administrators Guide.
Consider, for example, a large multidomain environment where there is a Personnel database in both the Manufacturing and the Sales domains. The domains fsi:[Manufacturing]Personnel and fsi:[Sales]Personnel allow accessing the two databases.
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NOTE |
Once an external file has been opened by a D3 process running in the VME, the file remains opened, even if the process drops back to TCL. External files are closed only when the user logs off. |
These topics are presented:
See Also