Because of their relatively small number, particularly violent or difficult inmates are housed in a single maximum-security facility. The key to management and control has been a group officer system in which 1 or 2 officers have specific responsibility for a group of up to 10 inmates. Officers meet regularly with inmates to discuss affairs within the facility. The officer is the inmate's first avenue of approach for difficulties or complaints. The Invernesse unit provides a secure and segregated setting for those inmates who have to be removed from their prison of classification until they are deemed to have demonstrated fitness to return to their original facility. While this segregation does result in some deprivation of privileges, it is used to isolate particularly disruptive inmates and provide a cooling off period for the inmate, the staff at the parent facility, and other inmates. The Barlinnie Special Unit, designed for long-term potentially violent and volatile inmates, emphasizes relative freedom within the unit, a close sense of community between inmates and staff, and inmate self-government. Other units house small groups of offenders in need of personal protection or disciplining. 4 notes and 20 references.