Formal Models of Operating System Kernels phần 5 pps
Formal Models of Operating System Kernels phần 5 pps
... to determine all the children of a parent process. 4.8 General Results This final section contains the proof of a number of propositions that deal with 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...
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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. ... interrupts occur 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 L...
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Formal Models of Operating System Kernels phần 10 pot
... 36 ΦCURRENTPROCESS q 53 ΨCURRENTPROCESS q 53 List of Definitions 3 25 IsLockedPage 257 IsPageExecutable 258 IsPageInMainStore 253 IsPageReadable 257 IsPageWritable 258 IsSharedPage 256 LatestPageCount 252 LockPage ... 254 MarkPageAsOut 255 MarkPageAsShared 256 NumberOfFreePages 248 PhysicalPageNo 250 RemovePageFromPageTable 253 RemovePageFromProcess 253 RemovePageProperties...
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Formal Models of Operating System Kernels phần 9 potx
... counter are: BIT == {0, 1} N 256 == 0 255 (N 256 is just the naturals 0 2 16 − 1—i.e., a 16-bit unsigned.) The computation of the counter value forms part of the predicate of schema ComputeHitCounts. ... N pgallocstart =0 The 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...
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Formal Models of Operating System Kernels phần 8 pot
... 238 5 Using Messages in the Swapping Kernel The procedures comprising the system- call library all send and receive messages. Therefore, the rest of the proof must be in terms of the properties of ... Natura, I, 155 6.1 Intro duction In this chapter, mechanisms to support virtual storage will be modelled. Vir- tual storage affords a considerable number of advantages to the operat...
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Formal Models of Operating System Kernels phần 7 doc
... present purposes—the modelling of kernels that are free from things like file systems—the approach adopted here seems quite reasonable. 5. 4 Drivers Using Messages 2 25 5.4.1 The Clock To begin the ... message contains the identifier of the sending process. It also contains two natural numbers (elements of N). They denote the size of the data area and the size of the stack area th...
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Formal Models of Operating System Kernels phần 6 pptx
... 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 ... of the current kernel. 5. 2 Requirements The requirement is to model an operating system kernel that is based upon the exchange of messages between processes. The kernel shoul...
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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 are no children of ... 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,...
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Formal Models of Operating System Kernels phần 3 ppt
... • parentof (p 1 , p?)) RemoveProcessFromParent ∆(parentof ) parent?, child?:APREF parentof = parentof \{(parent?, child?)} ParentOfProcess p?:APREF parent!:APREF (∃ p 1 : APREF • parentof (p 1 , ... +#s 2 = #s 1 +1+#s 2 = 1+#s 1 +#s 2 = 1+#elts ✷ Proposition 54 . Let q be readyqueues(p r ), where p r is the priority of process, p. If p is an element of q, then MakeUnready[p/pid?] imp...
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Formal Models of Operating System Kernels phần 1 pdf
... GeneralResults 198 5 Using Messages in the Swapping Kernel 203 5. 1 Introduction 203 5. 2 Requirements 204 5. 3 Message-PassingPrimitives 2 05 5.4 DriversUsingMessages 224 5. 4.1 The Clock 2 25 5 .5 SwappingUsingMessages ... 32 2.4 .5 Process Time Quanta 36 2 .5 Processes and the Process Table 39 2.6 ContextSwitch 51 2.7 Current Process and Ready Queue 52 3 A Simple Kernel 55...
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