Patent ID: 7418570
Filing Date: 2008-08-26
Classification: G06F

Abstract:
1. A logical unit number increasing device for increasing a number of logical units by using a virtual logical unit number allocated to a virtual logical unit and a plurality of real logical unit numbers allocated to a plurality of real logical units, respectively, said logical unit number increasing device comprising: a logical unit number conversion table defining a correlation between the virtual logical unit number allocated to the virtual logical unit and the real logical unit number of one of said plurality of real logical units; a host interface for receiving an access request specifying an access-destination virtual logical unit number from a host; a logical unit number converter, responsive to said access request from said host, for referring to said logical unit number conversion table and converting the virtual logical unit number specified by said access request into the real logical unit number correlated to said virtual logical unit number; a device director interface for feeding to a device director the access request in which the virtual logical unit number has been converted into the real logical unit number by said logical unit number converter; an access mode setter for setting an access mode correlated to said virtual logical unit number to “access forbidden”; and access denial device for denying an access based on an access request specifying said virtual logical unit number during a time when said access mode correlated to said virtual logical unit number is set to “access forbidden” by said access mode setter.