Chapitre 8

1

• Chapitre 8
• Hierarchie
• des mémoires

2
Cost of Memory
3
Memory Hierarchy
Speed
Registers
CPU Cache
Central Memory
Disk Cache
Disks
CD/ROM
Archival Stores
Size (log scale)
4
Cache principle
Cache
M E M O R Y
CPU
5
Fully Associative Cache
?
?
?
Page Number
?
Page Number
?
?
?
?
Word number within page
Data
6
Fully Mapped Cache
Page Number
?
Page Number
Word number within page
Data
Set Number
7
Set Associative Cache
?
Page Number
?
Page Number
Data
Word number within page
Set Number
8
Memory Management
Logical Addresses
Memory Management System
Physical Addresses
9
Memory Segmentation
Segment d
Segment a
Segment c
Physical Memory
Segment b
10
Segment Table
Logical Address
Segment Number
Offset

gt
int.
Physical Memory
Seg.addr.
Seg.length
r/w
Segment Table
11
Pagination
Logical Memory
Physical Memory
12
Page Table
Logical Address
Page Number
Offset
int.
Physical Memory
r/w
Pag.Nbr.
Page Table
13
Two levels page tables
Logical Address
Offset
Page Nbr.low
Page Nbr.high
Physical Memory
Page Table High
Page Tables low
14
Expanded Memory in PCs
Expanded Memory
(16 K pages)
Central Memory
15
Virtual Memory
Logical Address
Page Number
Offset
Mem.prot.int.
Central Memory
Page fault int.
r/w
Pag.Nbr.
p/c
Page Table
Peripheral Memory
16
Demand Paging
Progress of program
inst.n-2
inst.n-1
inst.n
inst.n1
Page Fault
Missing page is being loaded in central memory
by OS.
Interrupted program resumes
time
17
Segmentation Pagination
Logical Address
Offset
Page Nbr.
Segment Nbr.
Physical Memory
Segment Table
Page Tables
18
Translate Look Aside Buffer
Logical Address
Offset
Page Nbr.
Segment Nbr.
Page Fault Interrupt
?
Log.SegmentPage Nbr.
Ph.Page Nbr.
?
Physical Memory
?
?
Software
Segment Table
Peripheral Memory
Page Tables