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,...

Ngày tải lên: 23/07/2014, 23:20

... 36 usedsegment 244 userqueue 127 Function: addresstrans 242 after 146 , 270 codeToPSUs 152 dlogicalpage 242 dpageoffset 242 hole size 146 lower addr 146 mark page 244 memend 145 memsegoverlap 145 memsegsymoverlap ... 232 descriptor, 144 descriptors, 9 management, 8, 88, 144 , 2 04 segment, 239 unit primary, 145 Storage manager, 9 Store real, 240 virtual, 10, 11, 239 System call,...

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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 ... determine a number of properties of CCS and CSP processes, including observational equivalence and bisimilarity. The propositions concerning equivalence of the various versions...

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... 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 ... of sharedpages(p)(sg), for some p and sg. Proof. Similar to the previous proof. ✷ Proposition 1 34. IsLockedPage iff lpno? is a locked page; that is, iff lpno? is an element of loc...

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... 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 225 5 .4. 1 The Clock To begin the ... those components that are required to support message passing. The rest of the definition can be found in Section 4. 4 of Chapter 4. The differences between the ProcessTable required...

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... 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 ... the kernel of the previous chapter (Chapter 4) . The only difference between the two is that, whereas the kernel of Chapter 4 used semaphores, the current one uses messages. Figu...

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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 becau...

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... process. GetTimeQuantum tquant!:TIME currentquant = tquant! 4. 4 Process Management 121 ProcessHasParent p?:APREF (∃ p 1 : APREF • parentof (p 1 , p?)) RemoveProcessFromParent ∆(parentof ) parent?, child?:APREF parentof  = parentof \{(parent?, ... device queue is empty and the queue of system pro- cesses is not empty, ScheduleNext will select a system process as the next value of cu...

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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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... ConcludingRemarks 85 4 A Swapping Kernel 87 4. 1 Introduction 87 4. 2 Requirements 87 4. 3 CommonStructures 88 4. 3.1 Hardware 88 4. 3.2 Queues 93 4. 3.3 Process Queue 94 4.3 .4 Synchronisationand IPC 97 4. 4 Process ... Management 103 4. 5 TheScheduler 126 4. 6 StorageManagement 144 4. 6.1 SwapDisk 158 4. 6.2 Swapper 163 4. 6.3 Clock Process 173 4. 6 .4 Process Swapping 186...

Ngày tải lên: 23/07/2014, 23:20