COP 4610 Lecture Notes - Lecture 3: Busy Waiting, Code Segment, Nachos
25 Sep 2018
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Observable with multiple threads that are related to the same app. And to work well together : need synchronisation ex: acces to a variable. Independent process: execution of one process does not affect execution of others. Cooperative process:execution of one process affects execution of other process. Critical section problem: is a code segment that can be accessed by only one process at a time. Solution to critical section pb: needs to satisfy the following 3 conditions: 1-mutual exclusion : if a process is executing in its critical section then no other process is allowed to execute in cs. (correctness) 2-progress: processes that wants to enter into critical section has to be allowed (efficiency) 3-bounded waiting: afte(cid:396) p(cid:396)o(cid:272)ess asks to get i(cid:374) (cid:272)(cid:396)iti(cid:272)al se(cid:272)tio(cid:374), the(cid:396)e"s a ti(cid:373)e li(cid:373)it set o(cid:374)(cid:272)e access is granted for this process (fairness) Exit section each process that wanna exit goes throug exit section and so it.
