A CGI scripts is a program that is written in C,C++,or Perl.A CGI script gets executed in a server.When a aserver receives a request from the client for processing data,the server passes the request to the CGI script.The CGI script processes the request and sends the output in the form of HTML to the server.The server in turn passess the request to the client.
The disadvantages of using a CGI script are as follows:
a)Whenever a CGI script is involked,the server creates a separate process for it.The server has a limitation on the number of processes that can be created simultaneously.If the number of requests is too high,the server will not be able to accept the requests.In addition,creation of too many processes will also bring down the efficiency of the server.
b)The most popular platform for writing a CGI script is Perl.Even though Perl is a very powerful language for writing CGI applications.the server needs to load the Perl interpreter for each request that it receives.Thus,for an incoming request,the executable
file of the CGI script and the Perl interpreter are loaded,which brings down the efficiency of the server.
Unlike CGI scripts,the servlet initialization code is executed only once.In the case of servlets,each request is handled by a aseparate thread in the Web server.This helps to make the Web server more efficient by preventing creation of unnecessary processes.