Matakuliah
Tahun
Versi/Revisi
: T0316/sistem Operasi
: 2005
:5
Pertemuan 12
Manajemen Memory (Lanjutan)
OFFCLASS02
1
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• menjelaskan pengelolaan memory tingkat lanjut,
misalnya swapping, virtual memory (C2)
2
Outline Materi
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•
•
•
•
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Swaping
Memory management dgn Bit Map
Memory management dgn Linked List
Algoritma pengalokasian memori
Virtual memory
Page table
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Swapping (1)
Memory allocation changes as
– processes come into memory
– leave memory
Shaded regions are unused memory
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Swapping (2)
• Allocating space for growing data segment
• Allocating space for growing stack & data
segment
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Memory Management with Bit Maps
• Part of memory with 5 processes, 3 holes
– tick marks show allocation units
– shaded regions are free
• Corresponding bit map
• Same information as a list
6
Memory Management with Linked Lists
Four neighbor combinations for the terminating process X
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Algorithm for memory allocation
1.
2.
3.
4.
5.
First Fit
Next Fit
Best Fit
Worst Fit
Quick Fit
To speed-up search:
• Separate table for process and holes
• Hole list is sorted (eg ascending)
 Best fit = first fit; next fit is unnecessary
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Virtual Memory
Paging (1)
The position and function of the MMU
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Paging (2)
The relation between virtual
addresses and physical
memory addresses given by
page table
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Page Tables (1)
Internal operation of MMU with 16 4 KB pages
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Page Tables (2)
• 32 bit address
with 2 page
table fields
• Two-level page
tables
Top-level
page table
Second-level page tables
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Page Tables (3)
Typical page table entry
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TLBs – Translation Lookaside Buffers
A TLB to speed up paging
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Inverted Page Tables
Comparison of a traditional page table with an inverted page table
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