1 Pertemuan 15 Modelling Page Replacement Algorithm Matakuliah: T0316/sistem Operasi Tahun: 2005 Versi/Revisi: 5.

Presentasi berjudul: "1 Pertemuan 15 Modelling Page Replacement Algorithm Matakuliah: T0316/sistem Operasi Tahun: 2005 Versi/Revisi: 5."— Transcript presentasi:

1 1 Pertemuan 15 Modelling Page Replacement Algorithm Matakuliah: T0316/sistem Operasi Tahun: 2005 Versi/Revisi: 5

2 2 Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : menjelaskan permodelan algoritma pergantian page dan memprediksi page fault (C2)

3 3 Outline Materi Belady's Anomali Stack Algorithm Distance String Memprediksi Page fault

4 4 Modeling Page Replacement Algorithms Belady's Anomaly FIFO with 3 page frames FIFO with 4 page frames P's show which page references show page faults

5 5 Stack Algorithms State of memory array, M, after each item in reference string is processed 7 4 6 5

6 6 Stack Algorithms (2) Stack algorithm has the property of M(m, r)  M(m+1, r) where M  internal array m  number of page frames n  virtual pages r  index into the reference string  The set of pages included in the top part of M for a memory with m page frames after r memory references are also included in M for a memory with m+1 page frames  LRU has this property but FIFO does not  This algorithm do not suffer from Belady’s Anomaly m n … r …

7 7 The Distance String Probability density functions for two hypothetical distance strings

8 8 The Distance String Computation of page fault rate from distance string –the C vector –the F vector 3 3 3 1 0 8 9 11 14 17 20