Formal Models of Operating System Kernels phần 9 potx

... 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...

Ngày tải lên: 23/07/2014, 23:20

... 214 GENREGSET : INIT 90 GlobalVariables: INIT 213 missed ticks 213 HardwareRegisters: GetGPRegs 59, 92 GetIP 59, 92 GetStackReg 59, 92 GetStatWd 59, 92 INIT 91 SetGPRegs 59, 91 SetIP 59, 92 320 References 16. ... MA, 198 9. 36. Wirth N. and Gutknecht, J., The Oberon System, Software Practice and Expe- rience, Vol. 19, No. 9, 198 9. 37. Zhou, D. and Black, Paul E., Formal...

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 ... 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

... bound to the value of currentp by sched.CurrentProcess. ✷ Proposition 1 19. The receiver of a message is always the current process. Proof. By reasoning similar to the first paragraph of the previous ... prove some fairly general properties of the message-passing system. Proposition 112. The message-passing mechanism is synchronous. Proof. By the predicates of SendMessage and RcvMe...

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 ... respects to Tan- nenbaum’s Minix system [30], the precursor of Linux. The reason for this is that we believe that Minix is one of the superior examples of the method. (Xinu [9]...

Ngày tải lên: 23/07/2014, 23:20

... 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...

Ngày tải lên: 23/07/2014, 23:20

... 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

... • parentof (p 1 , p?)) RemoveProcessFromParent ∆(parentof ) parent?, child?:APREF parentof  = parentof \{(parent?, child?)} ParentOfProcess p?:APREF parent!:APREF (∃ p 1 : APREF • parentof (p 1 , ... priority of process, p. If p is an element of q, then MakeUnready[p/pid?] implies that p is not an element of q  . Proof. There are two cases to consider: Case 1. Process p is the head o...

Ngày tải lên: 23/07/2014, 23:20

... 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. ... 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 invari...

Ngày tải lên: 23/07/2014, 23:20

... a real help—I have used formal models as a way of trying out new software ideas since the late 198 0s). Of course, I hope that people from formal methods and operating systems, as well as computer ... 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 syst...

Ngày tải lên: 23/07/2014, 23:20