Iain D. Craig Formal Models Of Operating System

... future 7.2 Review The formal models of three operating systems have been presented All three kernels are intended for use on uni-processor systems They are also examples of how the classical kernel ... a proof of the correctness of the model for semaphores The second kernel is of approximately the complexity of kernels such as those built by Digital Equipment for the exc...

Ngày tải lên: 23/07/2014, 23:20

... : N pgallocstart = The value of is completely arbitrary, as is now explained Some systems map a virtual copy of the operating system onto the virtual address space of each user space (and some ... 1 89 If except? = ∅, ReleaseSegmentPagesExcept implies that the predicate of CanReleaseSegment is satisfied Proof The predicate of CanReleaseSegment is: dom pagetable(p?)(sg?) = ∅ The...

Ngày tải lên: 23/07/2014, 23:20

... comprising the system- call library all send and receive messages Therefore, the rest of the proof must be in terms of the properties of the message-passing subsystem The message-passing subsystem is ... element of sharedpages(p)(sg), for some p and sg Proof Similar to the previous proof Proposition 134 IsLockedPage iff lpno? is a locked page; that is, iff lpno? is an element of lock...

Ngày tải lên: 23/07/2014, 23:20

... creation and termination In most systems, the kernel also handles I/O requests, often at the level of the file system The above class is included as an illustration of what can be done and could, ... they are sent 5.3 Message-Passing Primitives 2 17 Proposition 116 Nothing happens in the system unless an interrupt occurs Proof The critical part of this is: when context switches occu...

Ngày tải lên: 23/07/2014, 23:20

... most significant aspect of this chapter’s model is that it acts as an existence proof It is possible to define a formal model of an operating system kernel and to prove some of its properties In ... exactly one of the following holds: If the new head of P If the new the end of If the new conditions value of pr is less than the old one, p will appear closer to the than in P v...

Ngày tải lên: 23/07/2014, 23:20

... existence proof It is intended to show that it is possible to model an operating system kernel, albeit a small one, using purely formal models The model is simple, as is the kernel—more extensive kernels ... reader an idea of some of the other things that might need to be handled during termination) If a process is on disk when it is terminated (say, because of system termin...

Ngày tải lên: 23/07/2014, 23:20

... closure of the childof relation; the complete set of descendants of a given process are represented by childof + (| {p?} |) for any process identifier p? In BlockProcessChildren, ps is the set of descendants ... descendant of the ancestor of the process just blocked Proof This requires the proof of the following lemma Lemma 16 For any process, p, BlockProcessChildren implies that...

Ngày tải lên: 23/07/2014, 23:20

... element of PREF but not of IPREF Proposition 37 ∀ p : APREF • p ∈ freeids ⇔ p ∈ known procs Proof This is a conjunct of the invariant Proposition 38 NewPId [p/p!] ⇒ p ∈ known procs Proof NewPId ... childof ∪ (child ?, parent?) DelChildOfProcess ∆(childof ) parent?, child ? : APREF childof = childof \ (child ?, parent?) AllDescendants descs! : F APREF parent? : APREF descs! = childof +...

Ngày tải lên: 23/07/2014, 23:20

... the characteristics of the classical operating system kernel, hence the duplication of the figure2 4.3 Common Structures In this section, some structures common to many of the models in this book ... Hardware Operating system kernels operate the system s hardware This subsection contains a number of definitions that will be used when defining the rest of the kernel The spe...

Ngày tải lên: 23/07/2014, 23:20

... Formal Models of Operating System Kernels Iain D Craig Formal Models of Operating System Kernels Iain D Craig, MA, PhD, FBCF, CITP British Library ... detailed descriptions of new systems1 The formal specification and derivation of operating system kernels is also of clear benefit to the real-time/embedded systems community Here, the kernels tend to ... C...

Ngày tải lên: 23/07/2014, 23:20

... modify a page of data at a time An attempt by a reader to write previously read data causes a memory fault which converts a reader into a writer and invalidates all other page caches A subsequent attempt ... when it initiates a cache replacement A data manager may restrict the use of cached data by issuing a pager_data_lock request, specifying the types of ac...

Ngày tải lên: 12/09/2012, 15:05

... coastal-zone management, integrated river basin management and/or ecosystem-based river basin management (Nakamura, 2003) Embedded in these approaches are the concepts of participatory management and adaptive ... and evaluating management strategies, is that of policy analysis 22 Chapter1 Policy analysis and rapid assessment models According to Miser and Quade (1985),...

Ngày tải lên: 06/11/2012, 10:35

... characteristics of the CLG processing model are the use of constrained terms to represent partial descriptions, the lack of systematic rewriting of constraints to normal form and the lazy evaluation of complex ... constraints between terms and formulas built from the atomic constraints using the standard logic operators, namely disjunction, conjunction and negation, and th...

Ngày tải lên: 18/03/2014, 02:20

... The AMALGHMA (Advanced Measurement Algorithms for Hardware Architectures) tool has been implemented for automating the measuring activities AMALGHMA adopts a set of statistical methods, such as ... the hardware model to carry out the performance and energy consumption estimation A tool, named PECES, was implemented for automatizing the method Additionally, a measuring pl...

Ngày tải lên: 21/06/2014, 11:20

... implementation, tradeoff, and conformance test Two case studies are presented: a real silicon device mixed-mode behavioral model of a CAN bus transceiver and a generic mixed-mode behavioral model of a ... VHDL-AMS hardware description language for the behavioral models implementation, due to the fact that it is an industrial standard modelling language and it is widel...

Ngày tải lên: 21/06/2014, 20:20