Client Server

ICOBOL Client/Server File Access

Shared file access support for Interactive COBOL applications in a client/server environment is provided via ICOBOL Client/Server File Access (ICNETD), an optional ICOBOL product that works in conjunction with the standard Runtime System. Requests are managed between the clients and the UNIX or Windows based server via a TCP/IP-based private protocol, so it is possible to install a client/server solution supporting a large number of different physical locations. ICOBOL Client/Server File Access is required for server environments where UNIX files are being shared, as well as in environments where UNIX and Windows file-sharing needs to exist. The product is not required for file-sharing in a Windows-only environment, but has the potential to dramatically improve performance, depending on the nature of the file access activity. Pricing for ICOBOL Client/Server File Access is determined by the maximum number of simultaneous clients connected to the server.

Currently, clients can be enabled via any one of the following methods:

• The ICOBOL Runtime System itself
• Applications built using the optional User Library product
• The ODBC Driver product

ICOBOL ThinClient

A second service that is provided by ICNETD is the support of the Client/Server runtime, also referred to simply as the ThinClient. There is a single version of the thin-client client in ICOBOL 4, which is called icrunrc, that provides both a character-mode interface, and a GUI-mode interface (using sp2). This means that an application can have a mixture of character screens and GUI screens, allowing GUI elements to be introduced into an old application in phases. This is unlike ICOBOL 3, which had separate character mode and GUI mode thinclient runtimes, requiring an all-or-nothing conversion to a GUI interface before taking advantage of thinclients. The client side is very compact because the application is running on the server. The server-side runtime, icrunrs, can be based on either a Windows server or a UNIX server (even when supporting GUI clients), and the server supports both ICOBOL 4 and ICOBOL 3 clients. All licensing is managed on the server which further simplifies the client deployment. The new thinclient also has an automatic reconnection facility (except when using HP-UX).

ICOBOL Remote Logging

The third service that is provided by ICNETD is remote logging and file mirroring. The logging facility, in general, tracks all of the modifications to any ICISAM file that has logging enabled. This allows for robust and quick data recovery procedures in the event of a system crash. The new remote logging service being introduced in ICOBOL 4 takes that concept even further by (1) allowing the log files to be on a different server in the network, and (2) allowing the ICISAM file to actually be mirrored on another server on the network. This provides the basis for a recovery system that allows for very quick server failover. It also allows for a read-only query server that is reading the up-to-date mirrored files without impacting the performance of the main server.