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The Sunbelt Data Manager adds exciting new features to any networked PL/B configuration. If you are currently using any of our Windows or Unix Sunbelt language products in a networked environment, you really need to take a look at what the Data Manager has to offer. With the Data Manager, you can:

• Improve performance of network based ISAM and AAM accesses

• Relieve network congestion caused by disk accesses

• Enhance data security by using encrypted communications

• Free client resources for other tasks

• Create a single point of control for the management of shared files

• Simplify the interface between various operating systems

• Replicate your data to up to 3 additional Data managers with automatic rollover capability.

With the Data Manager, a program requests a record via a sequential, random, ISAM, or AAM access. The Data Manager locates the record at the server using its local data files. Once the requested record has been found, the Data Manager sends only the data record back to the program. The Data Manager has been implemented in such a way that no programming changes or recompilations of your existing programs are required. You simply create a new file (Managed File Descriptor) using the MAKEMFD utility and describe the physical location of the actual data file. When a program opens the MFD, it will automatically link to the file on the server. You can also avoid using the Managed File Descriptor by adding the TCP/IP address of the Data Manager to the file name on the OPEN statement.

For years, PL/B programmers have relied on our Indexed Sequential Access Methods (ISAM) or Associated Access Methods (AAM) to solve complex data storage and retrieval issues. Sunbelt has led the way with ISAM products that offered both balanced tree (B+ tree) and deleted space recovery logic. Our unique AAM access methods are far superior to other technologies available today for free form searches. These technologies are a mainstay of our product line and keep our PL/B products at the forefront of programming languages.

Using PL/B in a networked environment seems simple enough from the programmer's standpoint. It can be completely transparent to the user whether the files accessed by the programs are stored locally or on the network server. The program simply opens the files on a redirected drive and the program behaves as usual. Well, almost.. There can be that issue of performance.

On a small, lightly loaded network disk access times may not be apparent. This is especially true if high speed network components are used. But, what would happen if that link was slower - perhaps it was even the Internet or, worse yet, a dial up Internet connection. Odds are that performance of any language would suffer in this configuration. That's not true with Sunbelt!

Let's start by examining what takes place during a normal ISAM read statement.

1. The program begins by passing the key of the record to be retrieved to the disk routine.
2. That routine starts its journey through the ISAM structure by reading the top level of the tree from the ISAM file.
3. The routine then determines the next level of the tree structure and reads that level from the file.
4. The process is repeated until the key is found in the lowest level of the index.
5. The lowest level of the index points to the location of the record in the data file.
6. That record is then read and the data returned to the program.

Next we introduce the network to the process. The program works just as it did before. The important thing to note is that each of the index file and data file reads now take place across the network. Even on a lightly loaded network, this is many times slower than access the local drive. Combine this with a busy network or a slower link and you can see there might be a performance issue.

Now, we implement the same logic using the Data Manager. We begin by executing a task on the server called the Data Management Task. This task waits for a network request by an application. When the application performs a disk access only the key is sent to the FMT. All the index and data file accesses needed to locate the record are done on the server by the Data Manager Task. Finally, the data is returned to the application. The result is that disk performance using the file manager across a network is on par with what you would expect with local disk access.

What about AAM you ask? It turns out that even though the Associated Access Methods have tremendous searching capabilities, the last stage of what they accomplish is done through a "brute force" method of disk access. When comparing networked AAM access to managed AAM access the numbers are even more impressive than ISAM.

The installation of the Data Manger is straight forward. Simply configure and initiate the task on the server. Next, you need to instruct your programs to use the managed files. There are 3 ways this can be accomplished.

1. Add new entries in the .ini file to point all accesses to the file manager. This is by far the easiest method as it requires no programming changes or new files, but the least flexible as all file opens and/or creates are redirected to the file manager.
2. Create managed file descriptors for each file to be opened via the Data Manager. Modify the program to open the managed file descriptors. If modifying the program is not an option or too difficult, simply create the managed file descriptors using the same names as the data files and place them in a new directory. Insert the directory in the PLB_PATH before the normal data directory and execute the programs. The OPEN statements will locate the managed file descriptors first and perform a managed open.
3. Modify the programs to append the file manager network address to each file name as it is opened. This is the most flexible in that some files can still be local while others are located using a specific file manager.

The Data Manager offers more capabilities beyond managed file support:

• Since Sunbelt offers both its language runtimes and the Data Manager for both Windows and Unix based systems, any combination or mix of clients and servers will work. You may have clients that are both Unix and Windows based while the Data Manager is running on a Unix machine. Just use your imagination! And, there is no Samba or NFS software to configure.

• The communications between the language runtime and the server may be optionally encrypted. This is especially important for business transactions using the Internet as a communication medium.

• Communications between the client and the server may optionally be compressed. This will increase performance and reduce network traffic even more.

• If you've ever needed to gain exclusive access to your data files for administrative purposes, you know what a nightmare it can be. Trying to get all the users (especially remote users) logged out of their applications at the same time can be trying. When using the Data Manager, the task becomes a breeze. By terminating the FMT, all the users will be disconnected and the files will be left in a clean state.

• Since the disk IO is taking place on the server, the client machine has more time and resources available to run other applications.

If you're still not convinced this product is right for you, why not take a thirty day test drive? Simply download the demonstration software and contact us for an authorization number. We think you'll be amazed at what the Sunbelt Data Manager can do for your network.