Managed File Support

Versions of PL/B prior to 8.4 were client side software only. Data and Index files could reside on a server but all processing took place on the workstation. The performance was generally quite good and was usually better than any other solution available.

With the general trend to more distributed networks over great distances, it was taking longer to access records in files located on a server that is not part of the local area network. ISAM performance was acceptable for lightly loaded systems, but in this situation AAM became virtually unusable because of the slow response time.

With Managed File Support, all of the dreary work of finding the record takes place on the server instead of the client. Both sides have to cooperate fully for the system to work.

With client only software, to READ an ISAM record requires at least three blocks of data to be examined (and it could be up to 10) to determine the location of the record before the record is read. To READ an AAM record for a large file could involve examining thousands of blocks of data before the correct record is found. With Managed File Support, the client sends the server the key(s) of the ISAM or AAM record to read. The server processes the read request locally where the access speed is much faster, finds the record and then sends the record back to the client.

The benefits of Managed File Support include no more long delays finding AAM records. Also, a drastic reduction in network traffic. The client machine can free up some time for background tasks since it is not looking at the ISAM and AAM information anymore. Possibly reduced phone charges since the client/server connection is made with TCP/IP protocol that the Internet uses. The user simply connects to the Internet, makes a connection to the server site, and starts using the files on the server. The server may be on a different continent, yet it is still just have a local call to the Internet Service Provider.

Managed File Support is implemented in both Windows and Linux. A Windows workstation can get data from a Linux host and a Linux workstation can get data from a Windows host.

For Windows, Managed File Support uses a Dynamic Link Library. The SUNODBC and SUNACCESS products both use the same DLL.

To implement Managed File Support, please refer to the MAKEMFD and SUNDM topics in the Sunbelt Utilities Reference.

Managed File support requires the purchase of a Sunbelt Data Manager product which is sold seperately.