3. user file
descriptor table file table inode table
0
file[100] inode[100] fd -> inode
am^/etc/passwd)
count D
j Read
u_ofile[15] „
k
0011111
«J ,
inode -> Disk
4.2 STRUCTURE OF A REGULAR FILE 69 j Rd-Wrf
^ (local)
f_inode
Data
Inode Blocks
direct „
(buffers[])
1
i count
1
1
i Write
direct
Figure 5.3. Data Structures after Open
i_addr[8] fdl - open("/etc/passwd", OJRDONLY);
fd2 - open ("local", 0_RDWR);
28
Process -> memory
INTRODUCTION TO THE KERNEL
direct , fd3 - open ("/etc/passwd", OJWRONLY);
per process
Figure 5.3 shows the relationship between the inode table, file table, and user file
direct descriptor data structures. Bach open returns a file descriptor to the process, and
the corresponding entry in the user file descriptor table points to a unique entry in
direct,
direct programmers to encode only two parameters.
u_procp
does not check the third parameter unless the second parameter indicates that it must, allowing
proc[50]
8
direct,
single
indirect p_addr?
double
indirect
coremap[100]?
triple
indirect
Figure 4.6. Direct and Indirect Blocks in Inode
4. User Program
User level trap Libraries (libc)
System call interface
Process
File system IPC
control
subsystem
Buffer cache Scheduler
char block Memory
Device drivers mng.
Kernel level Hardware control
Hardware level
Hardware
Bach
5. User Program
User level trap Libraries (libc)
System call interface
Section 1
( )
Process
File system IPC
control
subsystem
Buffer cache Scheduler
char block Memory
Device drivers mng.
Kernel level Hardware control
Hardware level
Hardware
Bach
6. User Program
Section 2
User level trap Libraries (libc)
System call interface
Process
File system IPC
control
subsystem
Buffer cache Scheduler
char block Memory
Device drivers mng.
Kernel level Hardware control
Hardware level
Hardware
Bach
7. User Program
User level trap Libraries (libc)
System call interface
Process
File system IPC
control
Section 3 subsystem
Buffer cache Scheduler
char block Memory
Device drivers mng.
Kernel level Hardware control
Hardware level
Hardware
Bach
8. User Program
User level trap Libraries (libc)
System call interface
Section 4
Process
File system IPC
control
subsystem
Buffer cache Scheduler
char block Memory
Device drivers mng.
Kernel level Hardware control
Hardware level
Hardware
Bach
9. User Program
User level trap Libraries (libc)
System call interface
Process
File system IPC
control
Section 5 subsystem
Buffer cache Scheduler
char block Memory
Device drivers mng.
Kernel level Hardware control
Hardware level
Hardware
Bach
10. 162 THE STRUCTURE OF PROCESSES
Figure 6.1. Process State Transition Diagram
