ДЇileAppend, %Philosopher% drops %This% fork. OutputDebug, %Philosopher% drops %This% fork. SetTimer, %Philosopher%WaitFor %Rand%ForkД®lse If (CurrentThisForkCount and CurrentWaitCount > 5 ) if we've been holding one of this fork too longД¬urrentThisForkCount - release other fork ДЇileAppend, %Philosopher% drops %Other% fork. OutputDebug, %Philosopher% drops %Other% fork. SetTimer, %Philosopher%WaitFor %This%Fork, OffД¬urrentOtherForkCount - release other fork the left one first.Д®ntry Greet when Guests 5 ) if we've been holding other fork too long Now the forks can be picked up in a 'wrong' order, i.e. So there are never more than four of them in there, which prevents deadlock. The following solution has a host of the room who chatters the last philosopher while four of them are in the room. Ph_5В : Person (Russel, Forks ( 1 )' Access, Forks ( 5 )' Access ) Д®nd Test_Dining_Philosophers Host of the dining room Д«oth deadlocks happen when all philosophers are in the dining room. Ph_4В : Person (Marx, Forks ( 4 )' Access, Forks ( 5 )' Access ) Ph_3В : Person (Spinoza, Forks ( 3 )' Access, Forks ( 4 )' Access ) Ph_2В : Person (Kant, Forks ( 2 )' Access, Forks ( 3 )' Access ) Ph_1В : Person (Aristotle, Forks ( 1 )' Access, Forks ( 2 )' Access ) 5 ) of aliased Fork - Forks for hungry philosophers Task type Person (IDВ : Philosopher First, SecondВ : not null access Fork ) ДЇorksВ : array ( 1. Philosopher tasks seize them in same order 1, 2, 3, 4, 5. The deadlock is prevented by ordering mutexes. In the following solution forks are implemented as plain mutexes. Null - Nothing to do in the main task, just sit and beholdД®nd Test_Dining_Philosophers Ordered mutexes Ph_1В : Person (Aristotle ) - Start philosophers

Put_Line (Philosopher'Image (ID ) & ' is leaving' ) Put_Line (Philosopher'Image (ID ) & ' is eating' ) LockВ : Set_Holder (Forks' Access, Cutlery' Access ) Put_Line (Philosopher'Image (ID ) & ' is hungry' ) Put_Line (Philosopher'Image (ID ) & ' is thinking' ) Дelay Duration (Random (Dice ) * 0.100 ) Life_SpanВ : constantВ := 20 - In his life a philosopher eats 20 timesДЇorksВ : aliased Mutexes_Array - Forks for hungry philosophersДЇunction Left_Of (ForkВ : Philosopher ) return Philosopher isД¬utleryВ : aliased Mutexes_SetВ := ID or Left_Of (ID ) Package Fork_Arrays is new Synchronization. Type Philosopher is (Aristotle, Kant, Spinoza, Marx, Russel ) When the the philosopher seizes his forks from the subset the array object prevents deadlocking since it is an atomic operation. The forks used by a philosopher compose a subset in the array. The following solution uses an array of mutexes in order to model the forks. 35.1 One solution based on Coro and AnyEvent.22.4 The structured derivation of the verb (function).22.3 Simulation of 22 chronological events for eight philosophers.22.2 Simulation of 11 chronological events for five philosophers.There are many solutions of the problem, program at least one, and explain how the deadlock is prevented. One deadlock state is when each philosopher has grabbed the fork left of him, and another is when each has the fork on his right. There exist two deadlock states when all five philosophers are sitting at the table holding one fork each. It can be observed that a straightforward solution, when forks are implemented by semaphores, is exposed to deadlock. After spending some random time thinking about the nature of the universe, he again becomes hungry, and the circle repeats itself. Eating takes random time, then the philosopher puts the forks down and leaves the dining room. When a philosopher cannot grab both forks it sits and waits. There are five forks on the table, one left and one right of each seat. For eating each philosopher needs two forks (the resources). They eat at a round table with five individual seats. It is a modification of a problem posed by Edsger Dijkstra.ДЇive philosophers, Aristotle, Kant, Spinoza, Marx, and Russell (the tasks) spend their time thinking and eating spaghetti. The dining philosophers problem illustrates non-composability of low-level synchronization primitives like semaphores. You are encouraged to solve this task according to the task description, using any language you may know.

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