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 , ... =0, it is an 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...

Ngày tải lên: 23/07/2014, 23:20

... end of P  than P. 3. If the new value of p r is the same as the old one, one of the two previous conditions will hold. Proof. By Proposition 21. The interesting case is case 3, whose proof follows from ... 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 so...

Ngày tải lên: 23/07/2014, 23:20

... buffer, 2 43 Unix, 5, 232 , 31 6 System V, 8 Unlock, 97 Unlock operation, 32 Virtual storage, 239 , 31 3 segment, 239 Virtual store, 31 4 and message passing, 31 0 block copy, 30 3 copy, 30 4 extending, 288 VMS, ... 97 LowLevelScheduler: allEmptyQueues 137 ContinueCurrent 137 CurrentProcess 132 GetTimeQuantum 131 INIT 130 MakeReady 132 MakeUnready 135 reloadCurrent 137 RunI...

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... 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 each user space (and some ... versions): VM 3 = init.(ISR | PFH 3 | Q | PD 2 | DSK | STORE) \{i, enq, deq, ok , done, get, init, s} where: PFH 3 = i.(enq.ok.0 | PFH 3 ) Proposition 167. VM 3 is observatio...

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... incore(p?)(sg?) ✷ Proposition 133 . IsSharedPage iff lpno? is a shared page; that is, iff lpno? is an element of sharedpages(p)(sg), for some p and sg. Proof. Similar to the previous proof. ✷ Proposition 134 . IsLockedPage ... OnPageRequest = 238 5 Using Messages in the Swapping Kernel The procedures comprising the system- call library all send and receive messages. Therefore, the rest...

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... al.’s fascinating and elegant Oberon system [35 , 36 ] is recommended). With these points noted, it is possible to move on to the use of the message- passing subsystem as defined above. The reader ... raiseRcvInterrupt[m!/msg!, ] 5.6 Kernel Interface 233 In order to provide these operations, a set of parameters must be defined for each operation. In each case, the identifier of the new...

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... 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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... 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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... 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...

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... RealandVirtualDevices 30 9 6.6 MessagePassinginVirtualStore 31 0 6.7 Process Creation and Termination; Swapping 31 1 7 Final Remarks 31 3 7.1 Introduction 31 3 7.2 Review 31 3 7 .3 FutureProspects 31 6 References 31 9 List ... broad. Formal Models of Operating System Kernels x Contents 3. 6 Current Process and Prioritised Ready Queue 77 3. 7 MessagesandSemaphoreTables 8...

Ngày tải lên: 23/07/2014, 23:20