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‫جامعة البعث‬ ‫كلية الهندسة المعلوماتية‬ ‫السنة الرابعة‬ ‫نظم تشغيل ‪2‬‬ ‫القسم النظري‬ ‫ر‬ ‫المحاضة ‪2‬‬  F -X C h a n ge F -X C h...

‫جامعة البعث‬ ‫كلية الهندسة المعلوماتية‬ ‫السنة الرابعة‬ ‫نظم تشغيل ‪2‬‬ ‫القسم النظري‬ ‫ر‬ ‫المحاضة ‪2‬‬  F -X C h a n ge F -X C h a n ge PD PD ! ! W W O O N N y y bu bu to to ww ww om om k k lic lic C C.c.c w w tr re tr re.. ac ac k e r- s o ft w a k e r- s o ft w a ‫اﻟﺪﻛﺘﻮر ﻃﺮﻳﻒ اﻟﻜﻠﺰﻟﻲ‬ ( )  F -X C h a n ge F -X C h a n ge PD PD ! ! W W O O N N y y bu bu to to ww ww om om k k lic lic C C.c.c w w tr re tr re.. ac ac k e r- s o ft w a k e r- s o ft w a ( )  F -X C h a n ge F -X C h a n ge PD PD ! ! W W O O N N y y bu bu to to ww ww om om k k lic lic C C.c.c w w tr re tr re.. ac ac k e r- s o ft w a k e r- s o ft w a. - ( )  F -X C h a n ge F -X C h a n ge PD PD ! ! W W O O N N y y bu bu to to ww ww om om k k lic lic C C.c.c w w tr re tr re.. ac ac k e r- s o ft w a k e r- s o ft w a -. - (... – ) (R1, R2, R3,…) - -. -. (Safe States).. : : : 9 3 P1 4 2 P2 7 2 P3 ( )  F -X C h a n ge F -X C h a n ge PD PD ! ! W W O O N N y y bu bu to to. : ww ww om om k k lic lic C C.c.c w w tr re tr re.. ac ac k e r- s o ft w a k e r- s o ft w a 9 3 P1 9 3 P1 9 3 P1 9 3 P1 - 0 P2 - 0 P2 - 0 P2 4 4 P2 - 0 P3 7 7 P3 7 2 P3 7 2 P3 3: 10 : 5: 9: 7: 0: 5: 1:. : 8: 9 4 P1 2: 4 2 P2 7 2 P3 Resource Allocation Graph Algorithm - - - -. -. ( )  F -X C h a n ge F -X C h a n ge PD PD ! ! W W O O N N y y bu bu to to ww ww om om k k lic lic C C.c.c w w tr re tr re.. ac ac k e r- s o ft w a k e r- s o ft w a Banker’s Algorithm -. -. -. m - n. m :.Rj k Available[ j ] = k nxm :.. Rj K Pi Max[i,j] = k nxm :.Rj K Pi Allocation[i,j] = k nxm :.Rj K Pi Need[i,j] = k –. n m Finish Work - Work := Available Finish[i] := false; i = 1,2,…,n. : i -2 Finish[i] = false Needi Work ( )  F -X C h a n ge F -X C h a n ge PD PD ! ! W W O O N N y y bu bu to to ww ww om om k k lic lic C C.c.c w w tr re tr re.. ac ac k e r- s o ft w a k e r- s o ft w a - Work := Work + Allocationi Finish[i] = true Finish[i] = true i - – Requesti[j] = k.Pi Requesti.Rj k Pi : Pi Pi Requesti Needi -. Requesti Available -. : Pi - Available := Available – Requesti ; Allocationi := Allocationi + Requesti ; Needi := Needi – Requesti ; Pi. : Allocation Max Available P1 5 4 1 10 6 2 3 2 1 P2 1 0 2 2 4 2 P3 0 4 0 4 6 1 P4 3 0 0 3 1 1 :... ( )  F -X C h a n ge F -X C h a n ge PD PD ! ! W W O O N N y y bu bu to to ww ww om om k k 1. Request1 = (4 0 1) lic lic C C.c.c w w tr re tr re.. ac ac k e r- s o ft w a k e r- s o ft w a 2. Request2 = (2 2 1) 3. Request3 = (2 1 0) : : Need P1 5 2 1 P2 1 4 0 P3 4 2 1 P4 0 1 1 : p4 Need(4) < Available, available =( 6 2 1) : p1 Need(1)< Available, available =( 11 6 2) p3 p2 (p4,p1,p3,p2) - - - (p4,p3,p1,p2) - ( ) (Detection & Resolution) Wait-for ) - (Graph - ( )  F -X C h a n ge F -X C h a n ge PD PD ! ! W W O O N N y y bu bu to to ww ww om om k k lic lic C C.c.c w w tr re tr re.. ac ac k e r- s o ft w a k e r- s o ft w a -.. m : nxm :.. nxm :.Rj k Pi Request[i,j] = k. n m Finish Work - Allocation 0 i = 1,2,…,n Work := Available. Finish[i] := true Finish[i] := false : i -2 Finish[i] = false Requesti Work - Work := Work + Allocationi Finish[i] = true. Finish[i] = false i - ( )  F -X C h a n ge F -X C h a n ge PD PD ! ! W W O O N N y y bu bu to to ww ww om om k k lic lic C C.c.c w w tr re tr re.. ac ac k e r- s o ft w a k e r- s o ft w a : Allocation Request Available A B C A B C A B C. P1 0 1 0 0 0 0 0 0 0 < P1, P3, P4, P2, P5> P2 2 0 0 2 0 2 P3 3 0 3 0 0 0 P4 2 1 1 1 0 0 P5 0 0 2 0 0 2 Request A B C. P1 0 0 0 P2, P3, P4, P5 P2 2 0 2 P3 0 0 1 P4 1 0 0 P5 0 0 2 Resource ) - (Preemption (Rollback) - (Process Termination) - ( )