• The Cathedral and the Bazaar

    November 27, 2006

    Regarding the issue of software engineering, we are reading a selection of works devoted various operating systems. The Cathedral and the Bazaar is about several things, The Linux development model The Sociology of the Linux development community Hints of software system design The Cathedral refers to the traditional software development practice, quoting from the paper: […]

  • Formal Security Models

    November 17, 2006

    We discussed the Bell-LaPadula model, the Biba model, and the Chinese-Wall model. The Bell-LaPadula model is concerned mainly with confidentiality. It explains and mimics the government’s security mechanisms of classification and compartmentalization. Subjects of this model have security clearances. Objects have security classifications. In the United States the classifications are Confidential, Secret, Top Secret, depending […]

  • Groups, Escalation and Impersonation

    November 17, 2006

    The access matrix captures the fixed rights mediating subject-object relations. There are other aspects which need to be considered for there to be a working security model. The Unix suid bit is an interesting and absolutely essential invention. Whatever it adds to the simple security model of Unix must be an absolute necessity. The suid […]

  • Protection

    November 13, 2006

    Protection is one of the fundamental responsibilities of an operating system. This includes protection of the operating system itself, so that it continues to run correctly and according to expectations, and protection promised user programs and data objects. Protection comes in various forms: Confidentiality: information can be viewed only by certain parties; Integrity: that things […]

  • Search

    November 3, 2006

    We are discussing two important methods for storing items in a data set in order to support fast finds, inserts, and sometimes additional operations, notably, deletion. The two methods are hashing and trees. Hashing provides very fast, O(1), access to items, but it is not guarenteed. Trees provide acceptibly fast, O(log n), access, support deletion […]

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