D3 file system interface server configuration

The D3 file system has fully distributed architecture and supports the D3 database. Any element of the file system can be on any server on the network, transparent to all applications.

The D3 file system main features include:

Full Client server architecture
Variable record length of up to 2 GB
Complete transparency—Records can contain any type of data
Maximum table size of 2 terabytes per table
Unlimited number of tables in a database
Object-oriented architecture
Application development tools in BASIC and FlashBASIC.

File servers
The D3 file servers on a network can run Windows Server and Windows Client. A D3 file server must be started on every machine on the system that has at least one D3 file on its local or mapped disks.
Client system, client thread, and client-ID
The client system can be any system running Windows Server or Windows Client. A client system is identified by its unique network computer name. A client system can also be a server. The client system is the basic unit when it comes to licensing.
Windows network setup
A Windows-based network can be configured either as a Domain or a Workgroup. Because of the superior security administration, the domain configuration is recommended.
Network domain
The network domain is a notion that defines a set of D3 Servers and Clients on a network. On Windows, it matches the Windows domain. Because of this one-to-one relationship, a network domain in D3 terminology is simply called a domain.
Directory structure
The various pieces of the file system on a given server are stored in a multilevel tree structure that has the following structure ($HOME represents the default directory of the FSI Server):
MDS
The MDS is the root of the D3 file system. It contains pointers to the databases. It is located on a special server on the network and designated as the Network Controller. Normally, the network controller would be the Domain Controller. The D3 FSI Server running on the network controller acts as a file server for both the MDS and the ordinary accounts and files located on this system.
Database
The database is the main element the application works with. A database is a collection of related application tables. The root of the database table structure is the master dictionary (MD), which contains pointers to the various tables in the database.
Table naming conventions
A D3 table name is composed as shown below.
Distributed record locks
Record locks are maintained by the server that holds the table. There is a record lock table per section of table, one for the dictionary and one for each data level, to ensure low conflicts between threads. The D3 File Manager applet shows the outstanding locks and can clear them. There is no limit on the number of record locks that can exist on the network.
File system memory usage
This topic explains the mechanisms involved in internal memory management. This explanation is intended only to help in system configuration and tuning, and to understand the various performance counters explained in the D3 User’s Guide.