Formal Models of Operating System Kernels phần 10 pot

... future.7.2 ReviewThe 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 ... proof of the correctness of the model forsemaphores.The second kernel is of approximately the complexity of kernels such asthose built by Digital Equipment for the excellent operating systems ... 67, 106 destruction, 84device, 106 , 127idle, 40, 68, 103 , 127reference, 42, 56, 103 management, 103 null, 40, 68, 103 reference, 42, 56, 103 page allocation, 301parent, 118priority, 106 reference,...

Formal Models of Operating System Kernels phần 9 potx

... Npgallocstart =0The value of 0 is completely arbitrary, as is now explained.Some systems map a virtual copy of the operating system onto the vir-tual address space of each user space (and some ... determine a number of properties of CCS and CSP processes, including observational equivalence andbisimilarity. The propositions concerning equivalence of the various versions of the subsystem were ... between the component processes of the subsystem, notin the speciﬁcation of the components. The processes to be modelled do nothave properties suggestive of the use of the π-calculus (e.g., mobility),...

Formal Models of Operating System Kernels phần 8 pot

... comprising the system- call library all send and receivemessages. Therefore, the rest of the proof must be in terms of the properties of the message-passing subsystem.The message-passing subsystem is ... 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 lockedpages.Proof. ... being“in core”, hence the name of the variable, incore.Thepagecount counts thenumber of pages in each segment of each process. There is an a priori limit tothe number of pages in a segment and pagecount...

Formal Models of Operating System Kernels phần 4 pot

... 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 there areno children of ... closure of the childof relation; the complete set of descendants of a given process are represented by childof+(|{p?}|) for any process identiﬁerp?. In BlockProcessChildren, ps is the set of descendants ... p,BlockProcessChildren ⇒ (∀ p1: APREF | childof (p1, p) • p ∈ ran userqueue )Proof. The predicate of BlockProcessChildren contains an instance of MakeUnready inside the scope of the universal quantiﬁer. The...

Formal Models of Operating System Kernels phần 7 doc

... message contains the identiﬁer of the sending process. Italso contains two natural numbers (elements of N). They denote the size of the data area and the size of the stack area that are, respectively, ... prove some fairly general properties of themessage-passing system. Proposition 112. The message-passing mechanism is synchronous.Proof. By the predicates of SendMessage and RcvMessage.If the ... design. However, many readers will, asa result of reading standard texts, be of the (false) opinion that kernels mustbe interrupt-driven. The kernel of the last chapter was driven, in part, by...

Formal Models of Operating System Kernels phần 6 pptx

... most signiﬁcant aspect of this chapter’s model is that it actsas an existence proof. It is possible to deﬁne a formal model of an operating system kernel and to prove some of its properties. In ... of the current kernel.5.2 RequirementsThe requirement is to model an operating system kernel that is based uponthe exchange of messages between processes. The kernel should be an example of ... cannot be used. Indeed, it is of a complexity not far from that of thetiny kernels used for embedded and some real-time systems. The µC/OS [18]is a good example of such a kernel.The kernel...

Formal Models of Operating System Kernels phần 5 pps

... to determine all the children of a parent process.4.8 General ResultsThis ﬁnal section contains the proof of a number of propositions that dealwith properties of the kernel.The propositions ... 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 ter-mination or because of some error ... enabling it to be represented withinthe system. As part of this, a test (proctab.CanGenPId)ismadeastowhetherthe system has reached its maximum number of processes. The schema is com-plicated...

Formal Models of Operating System Kernels phần 3 ppt

... •parentof (p1, p?))RemoveProcessFromParent∆(parentof )parent?, child?:APREFparentof= parentof \{(parent?, child?)}ParentOfProcessp?:APREFparent!:APREF(∃ p1: APREF •parentof (p1, ... priority of process,p. If p is an element of q, then MakeUnready[p/pid?] implies that p is notan element of q.Proof. There are two cases to consider:Case 1. Process p is the head of q. The ... ⊆ known procs ∧ dom childof ⊆ known procsran childof ⊆ known procs ∧ ran childof = ran parentchildof∼= parentof ∧ code owners ⊆ dom parentof(∀ p1, p2: APREF •p1∈ dom blockswaiting...

Formal Models of Operating System Kernels phần 2 pps

... performed, the inclusion of IdleProcRef and the ex-clusion of NullProcRef are of some importance. They determine the range of possible values for the domains of the components of process descriptors. ... interruptsoccur during the execution of a piece of code. They are used as a kind of low-level mutual exclusion mechanism.4.3 Common Structures 101 Proof. By a previous Lemma (Lemma 5), | scnt| ... the idle process, of course.Proof. The components of the process description, pstate, pkind, pstack,pregs, etc., all have identical domains by the ﬁrst part of the invariant of PROCESSES.Thatis:dom...

Formal Models of Operating System Kernels phần 1 pdf

... the upper layers of an operating system. OS Kit is a software kit, not a formal speciﬁcation or modellingtool.Iain D. Craig Formal Models of Operating System Kernels ContentsPreface vii1 ... written.This was one of the reasons for writing [10] . In addition to that book, formal models and proofs were used by the author as a way of exploring a number of new systems during the 1990s ... a real help—I have used formal models as a way of trying out new software ideas since the late 1980s). Of course, I hope that people from formal methods and operating systems,as well as computer...

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