Critical Section Problem With Two Process Solution (Algo-1) Deckers solution, Strict Alteration.<\/p>\n
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The Critical Section Problem<\/strong> is a classic problem in operating systems and concurrent programming, where multiple processes need to access shared resources without causing data inconsistencies. One of the earliest solutions for two-process synchronization is Strict Alternation<\/strong>, also known as Dekker\u2019s Algorithm (Algo-1)<\/strong>.<\/p>\n Concept:<\/strong> Let:<\/p>\n Process P0:<\/strong><\/p>\n Process P1:<\/strong><\/p>\n To overcome the drawbacks of strict alternation, Dekker’s Algorithm<\/strong> introduces an additional mechanism using flags ( Would you like a detailed explanation of Dekker\u2019s Algorithm<\/strong> or other alternative solutions like Peterson\u2019s Algorithm<\/strong>?<\/p>\n The Critical Section Problem<\/strong> arises in concurrent programming<\/strong> when two or more processes need mutual exclusive access<\/strong> to a shared resource<\/strong> (like a variable or a file).<\/p>\n Here\u2019s a breakdown of Algorithm 1: Strict Alternation<\/strong> and Dekker\u2019s Algorithm<\/strong>, which are classic solutions for the two-process critical section problem<\/strong>.<\/p>\n A good algorithm must satisfy the following:<\/p>\n Mutual Exclusion<\/strong> \u2013 Only one process in the critical section at a time.<\/p>\n<\/li>\n Progress<\/strong> \u2013 If no process is in the critical section, one of the waiting processes can enter.<\/p>\n<\/li>\n Bounded Waiting<\/strong> \u2013 No process waits forever to enter its critical section.<\/p>\n<\/li>\n<\/ol>\n This is the simplest solution but not efficient<\/strong>.<\/p>\n A shared variable Strict Alternation Solution (Algorithm-1)<\/strong><\/h3>\n
In the strict alternation method, processes take turns to enter their critical section by maintaining a shared variable turn<\/code>.<\/p>\nAlgorithm<\/strong><\/h4>\n
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turn<\/code> be a shared variable that alternates between 0 and 1.<\/li>\nP0<\/code> and P1<\/code> be the two processes.<\/li>\n<\/ul>\n\n
while<\/span> (turn != 0<\/span>); \/\/ Wait until it's P0's turn<\/span>
\n\/\/ Critical Section<\/span>
\nturn = 1<\/span>; \/\/ Give turn to P1<\/span>
\n<\/code><\/div>\n<\/div>\n<\/li>\nwhile<\/span> (turn != 1<\/span>); \/\/ Wait until it's P1's turn<\/span>
\n\/\/ Critical Section<\/span>
\nturn = 0<\/span>; \/\/ Give turn to P0<\/span>
\n<\/code><\/div>\n<\/div>\n<\/li>\n<\/ol>\nIssues with Strict Alternation<\/strong><\/h3>\n
Lack of Progress:<\/strong><\/h3>\n
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turn<\/code>, leading to CPU wastage.<\/li>\n<\/ul>\n<\/li>\n\n
Improved Solution: Dekker\u2019s Algorithm<\/strong><\/h3>\n
flag[0]<\/code> and flag[1]<\/code>) to ensure mutual exclusion while allowing flexibility.<\/p>\n
\n\u2705 Goal of a Critical Section Solution<\/h2>\n
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\n\ud83d\udd39 1. Strict Alternation (Algorithm 1)<\/strong><\/h2>\n
\ud83d\udd27 Idea:<\/strong><\/h3>\n
turn<\/code> is used to strictly alternate between processes.<\/p>\n