A user configurable 
RAID system designed to provide 
RAID functions as well as 
mass storage functions in a non-
RAID mode. Flexibility is built into the 
system to allow the user to configure the 
SCSI bus to which removable drive modules are connected into one or more channels to define some of the drive modules in a RAID set and others as stand-alone drives which are independently operated or logically grouped and operated in a non-RAID mode. Removable internal 
SCSI bridges allow the 
SCSI bus to be configured into one or more channels. In the RAID mode, the 
system is configured to prevent a wrong drive from being removed from the system in the event of a drive failure. The system automatically unlatches only the failed drive. The RAID system includes an 
intelligent control unit ("ICU"), a RAID controller and a modem. The ICU allows the 
system administrator to access the RAID 
system Monitor Utility so that the status of the system may be monitored and its configuration changed. The ICU also monitors the failure status of the various components of the system. The ICU has a built-in 
pager feature that can be configured with the Monitor Utility to page the 
system administrator via the modem when a component or 
system failure is encountered. The RAID controller controls the functions of the RAID set as programmed and configured using the Monitor Utility. The Monitor Utility may be remotely accessed using a computer via the modem. Redundant removable power supply and fan units are provided to improve 
system integrity. The removable power supply and fan units are configured such when the unit is plugged into the system housing, the fan is first turned on and the power through the unit is allowed to stabilize before turning on the power supply to begin providing DC power to the components in the system. A set of manual release buttons are provided for manually unlatching the drive modules from the system housing. A 
locking mechanism is provided for simultaneously locking all the manual release buttons.