3.1 Features of Various Web Link Functions

The following table lists the features of COBOL Web link functions.

		Link function
		ISAPI subroutines	CGI subroutines
Features	Web Server that can be used	IIS	All servers supporting CGI
	Web Interface technology	ISAPI	CGI
	File format activated by Web Server	DLL	EXE
	Operation model	Thread	Process
	Loading mechanism of COBOL applications executed on Web Servers	It is loaded at the first request to the application, then resides in memory for the next request.	It activates a process for each request to the application, and discards the process after processing ends.
	Execution performance	High-speed performance by multithreaded operation or DLL pre-load function.	Low-speed performance due to the overhead caused by a separate process activated/deleted for each request.
	User/Application Interface	HTML Web subroutines
	Ease of generating a business application	Because the interfaces with Web Servers are hidden in Web subroutines complying with the COBOL language specification, no special knowledge regarding Web is required.
	Utilization of existing resources	The actual business logic of existing applications can be mostly used without being modified significantly. However, interfaces with Web Servers are required, so the description for using Web subroutines must be added and the business logic must be organized to make use of such.
	Forms printing	The server can execute forms printing contained in the application. However, the printing function of the Web Browser or the downloaded application may be used by the client.
	Merit	Applications with high performance and resources consumed in small quantities can be generated by multithreaded operation.		Applications with high independence can be generated, independent of the server.

Note

The above table shows the outlined information for arranging the features of various Web link functions in rows.

For more detailed information, related products, and notes, refer to the manual corresponding to each Web link function.