Product manual

CDA 7 Input/Output Operations
77 A1 69UP Rev00 3-7
DISK
DIRECTOR
CACHE
DIRECTORY
CHANNEL
DIRECTOR
CACHE
DIRECTORY
CHANNEL
DIRECTOR
DISK
DIRECTOR
CACHE
DIRECTORY
CACHE
DIRECTORY
CHANNEL
DIRECTOR
CHANNEL
DIRECTOR
1 Cache Directory Search - Hit
2 Transfer to Host
3 Update Directory
1
2
3
1
2
1 Cache Directory Search - Miss
2 Position R/W Head, Stage
Data to Cache
3 Transfer to Host
4 Update Directory
READ HIT READ MISS
1 Cache Directory Search - Hit
2 Transfer to Cache
3 Update Directory
4 Asynchronous Destage
1 Cache Directory Search -
Cache is Full
2 Destage Page
3 Update Cache/Directory
4 Transfer to Cache
5 Update Directory
6 Asynchronous Destage
FAST WRITE
DELAYED FAST WRITE
21
4
4 1
3
2, 6
CHANNEL CHANNEL
DISK
DIRECTOR
DISKS DISKS
CHANNEL CHANNEL
3 5
DISKS
DISKS
DISK
DIRECTOR
34
Figure 3-5. Types of CDA 7 I/O Operations