J. Vochteloo, S.Russell, and G. Heiser. Capability-based protection in the Mungi operating system. In Proceedings of the 3rd International Workshop on Object Orientation in Operating Systems, pages 108-115. IEEE, December 1993.  Home/Search   Document Details and Download   Summary   Related Articles   Check

.... pointed out the poor operating systems support for database management systems requirements [58] Representative projects having taken into account such requirements include the work on Mach s external mapers [64] single address space operating systems such as Angel [46] Opal [21] and Mungi [62], persistent virtual shared memories such as ARIAS [29] and RVM [54] re ective operating systems such as Apertos [63] orthogonal persistent operating systems such as Grasshoper [27] and Charm [37] Projects trying to provide toolkits for the construction of database management systems can be ....

J. Vochteloo, S.Russell, and G. Heiser. Capability-based protection in the Mungi operating system. In Proceedings of the 3rd International Workshop on Object Orientation in Operating Systems, pages 108-115. IEEE, December 1993.

....in the object oriented community as they allow secondary storage to be unified with primary storage and remove the need for pointer swizzling. Security and protection are a major problem with single address space systems, and current approaches either rely on hardware assistance (Opal and Mungi [196]) software capabilities (Arias) or probabilistic algorithms [204] 3.3.2 Separate shared address spaces Another approach is to divide each process s address space into different fixed regions, some of which are private and not shared, and some of which are shared with some other processes. Ra, ....

Jerry Vochteloo, Stephen Russell, and Gernot Heiser. Capability-Based Protection in the Mungi Operating System. In Proceedings of the 3rd International Workshop on Object-Orientation in Operating Systems [94], pages 108--115.

....with the object. The entry point address must be registered with the system, and the caller must have a capability to this entry point. Figure 1 illustrates how the protection domain (shaded) associated with a thread changes during a PdxCall( The Mungi protection model is described in detail in [27]. Figure 1. PDX Protection Domains 3. Protected Components This section describes the protection features of a component model being developed on the Mungi SASOS. 3.1. Method Execution in an Amplified Domain Figure 2 shows the basic architecture of the component system, in which component ....

J. Vochteloo, S. Russell, and G. Heiser. Capability-based protection in the Mungi operating system. In Proceedings of the 3rd IEEE International Workshop on Object Orientation in Operating Systems (IWOOOS), pages 108--15, Asheville, NC, USA, Dec. 1993. IEEE.

....its implementation. This work was supported by Australian Reseach Council grant A49330285. y Phone: 61 2 9385 5156, fax: 61 2 9385 5995, e mail: disy cse.unsw.edu.au, www: http: www.cse.unsw.edu.au disy 2. Protection Domains in Mungi Mungi s basic protection model has been described in [VRH93] In short, each task (which consists of one or more threads) has associated with it a protection domain, which is the set of objects accessible to the task. The protection domain is implemented as a set of pointers to capability lists, which are arrays of capabilities. Contrary to classical ....

Jerry Vochteloo, Stephen Russell, and Gernot Heiser. Capability-based protection in the Mungi operating system. In Proceedings of the 3rd International Workshop on Object Orientation in Operating Systems, pages 108--15, Asheville, NC, USA, December 1993. IEEE.

....for control over page residency and physical I O can be accommodated. An approach to user level implementation of distributed shared memory (DSM) coherency models is outlined. 1 Introduction Single address space operating systems (SASOS) such as Angel [MSS 93] Opal [CLF 94] and Mungi [VRH93] are based on the idea that a single, large virtual address space holds all data in a (potentially distributed) computing system. It has been pointed out before [RSE 92] that this class of operating systems provides a natural solution to an old problem of persistent programming: How to save ....

Jerry Vochteloo, Stephen Russell, and Gernot Heiser. Capability-based protection in the Mungi operating system. In Proceedings of the 3rd International Workshop on Object Orientation in Operating Systems, pages 108--15, Asheville, NC, USA, December 1993. IEEE.

....which are described below. Threads are the basic execution abstraction. A task is a set of threads which share a protection domain. A protection domain consists of a set of capabilities. Capabilities are presented implicitly by storing them in a special data structure known to the system [19]. This reduces the need for most applications to deal with capabilities and thus makes protection transparent. Mungi is a pure SASOS in that it provides no inter process communication facility other than shared memory (plus semaphores for synchronisation) Furthermore, there are no explicit ....

J. Vochteloo, S. Russell, and G. Heiser. Capability-based protection in the Mungi operating system. In Proceedings of the 3rd International Workshop on Object Orientation in Operating Systems, pages 108--15, Asheville, NC, USA, December 1993. IEEE.

....(segregated) method needs the kernel to be invoked for every passing, comparing or storing of a capability, an unacceptable overhead in any system that has a strong commitment to providing support for sharing. It is for this reason that Mungi protection is implemented using password capabilities [VRH93] The other implementations of sparse capability were rejected due to the need for encryption which is computationally expensive. Sparse capabilities in general, but particularly password capabilities, have the advantages that are listed below. ffl Password capabilities allow the passing of ....

Jerry Vochteloo, Stephen Russell, and Gernot Heiser. Capability-based protection in the Mungi operating system. In Proceedings of the 3rd International Workshop on Object Orientation in Operating Systems, pages 108--15, Asheville, NC, USA, December 1993. IEEE.

....by the process and, assuming there are no conflicts, the object is placed into the domain. Modification of permissions trees is controlled by additional permissions bits, defining which processes can modify the trees and thus preventing security being compromised. Mungi s protection model [VRH93] is based on password capabilities [APW86] Capabilities may confer read, write, execute and delete rights. The password associated with each capability is a large random number chosen by the object s owner. Multiple capabilities may be created with the same rights but different passwords, ....

Jerry Vochteloo, Stephen Russell, and Gernot Heiser. Capability-based protection in the Mungi operating system. In Proceedings of the 3rd International Workshop on Object Orientation in Operating Systems, pages 108--15, Asheville, NC, USA, December 1993. IEEE.

....of the objects being referenced by the processes on a host. This leads to a drastic increase of the number of objects that must be managed, and further fragments the page table. The protection models in these systems are generally based on lists of capability that are maintained for each process [VRH93] The capabilities are used at run time to establish mappings with the appropriate protection bits. As activity switches between processes it is necessary to quickly change the protection bits without affecting the translation. As well, there needs to be support for quickly changing the ....

J. Vochteloo, S. Russell, and G. Heiser. Capability based protection in the Mungi operating system. In 3rd Int'l Workshop on ObjectOrientation in Operating Systems. IEEE, 1993.

....of database systems for control over page residency and physical I O can be accommodated. An approach to user level implementation of distributed shared memory (DSM) coherency models is outlined. 1 Introduction Single address space operating systems (SASOS) such as Angel [1] Opal [2] and Mungi [3] are based on the idea that a single, large virtual address space holds all data in a (potentially distributed) computing system. It has been pointed out before [4] that this class of operating systems provides a natural solution to an old problem of persistent programming: How to save arbitrary ....

J. Vochteloo, S. Russell, and G. Heiser. Capability-based protection in the Mungi operating system. In Proceedings of the 3rd InternationalWorkshopon Object Orientationin OperatingSystems, pages 108--15, Asheville, NC, USA, December 1993. IEEE.

....to provide hardware support for timestamps. Use of the timer also allows measurement of CPU usage by the instrumentation system. E mail: disy vast.unsw.edu.au 1 Introduction The instrumentation system presented in this paper forms part of the Mungi single address space operating system project [1,2,3,18] at the School of Computer Science and Engineering at the University of New South Wales. The purpose of this tool is to enable researchers to capture operating system kernel event traces to be used in simulation studies of memory management for Mungi. Instrumentation of the paging and filing ....

J. Vochteloo, S. Russell, and G. Heiser. Capability-Based Protection in the Mungi Operating System. In IEEE International Workshop on Object Orientation in Operating Systems, Asheville NC, 1993.

....the system derives a full set of capabilities from the owner capability and enters them into the OT. Unlike Amoeba, an owner can also create new capabilities and remove existing ones, which allows selective revocation of object access. Further details on the derivation scheme are presented in [36]. 4.3 The Capability Tree Data structures are needed to allow users to store and manipulate their capabilities, as well as allowing the system to quickly find capabilities while validating a memory access. Ideally, these data structures should also reflect the user s intuitive view of the ....

J. Vochteloo, S. Russell, and G. Heiser. Capability-based protection in the Mungi operating system. In Proceedings of the 3rd International Workshop on Object Orientation in Operating Systems. IEEE, 1993.

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