Portable device and a method for accessing a computer resource of a temporary registered user

A management method in a portable device connectable to a network system, comprising:

• acquiring access right information of a computer resource assigned to a user temporarily registered to the network system, from a computer which manages the computer resource in the network system;
• preserving the access right information acquired;
• accessing the network system using the access right information preserved;
• sending a temporary registration request to the computer in response to a request of temporary registration from the user;
• sending an extension registration request to the computer in response to a request of extension of a use period of the computer resource from the user, when a message that the present time is near the end of the use period and asking whether the user postpones the use period is received from the computer;
• and
• receiving a message that use of the computer resource is completed from the computer, if the extension registration request is not sent.