Mechanisms for Persistence and Security in BirliX

Abstract

BirliX is an operating system kernel supporting fault tolerant and secure applications in a distributed environment. Essentially it is an abstract data type management system. Its basic services are the definition of abstract data types, their instantiation, their identification, and the communication between instances. All abstract data types share a common set of type-independent attributes inherited from the kernel-defined BirliX Primary Type.

BirliX Types are persistent. Persistence of an instance depends on long term name bindings within nameservers, short term references form other instances, and internal instance activities. The kernel maintains an instance as long as there is at least one name binding, one external reference or an internal instance activity. Persistence of BirliX Types is based on persistent memory segments.

Security in BirliX is also based upon BirliX Types. Depending on their role during access, instances are classified as subjects (accessing instances) or objects (accessed instances). Access rights can be controlled from the point of view of subjects, called subject restriction lists (SRLs), and from the point of view of used objects, called access control lists (ACLs). The resulting granted access rights are the intersection of the granted rights as specified by ACLs and SRLs.