1. Chapter 2. System Structures
Operating System Concepts 8th Edition
Chapter 2. System Structures
Gan Lin, OSLab. GNU

2. - Ch.2 System Structures -
Contents
2.1 Operating-System Services
2.2 User Operating-System Interface
2.3 System Calls
2.4 Types of System Calls
2.5 System Programs
2.6 Operating-System Design and Implementation
2.7 Operating-System Structure
2.8 Virtual Machines
2.9 Operating-System Debugging
2.10 Operating-System Generation
2.11 System Boot
2.12 Summary
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3. - Ch.2 System Structures -
Objectives
To describe the services an operating system provides to users, processes, and other systems.
To discuss the various ways of structuring an operating system.
To explain how operating systems are installed and customized and how they boot.
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4. 2.1 Operating-System Services
user and other system programs
GUI
batch
command line
user interface
system calls
program execution
I/O operations
file
systems
communication
resource allocation
accounting
error detection
protection & security
services
operating system
hardware
Fig. 2.1 A view of operating system services
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5. 2.2 User Operating-System Interface
Command Interpreter
Graphical User Interfaces
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2.3 System Calls
Example System Call Sequence
Acquire input file name
Write prompt to screen
Accept input
Acquire output file name
Open the input file
if file doesn't exits, abort
Create out file
if file exits, abort
Loop
Read from input file
Write to output file
Until read fails
Close output file
Write completion message to screen
Terminate normally
source file
Fig. 2.2 Example of how system calls are used
destination file
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2.3 System Calls
API(Application Programming Interface)
- Win32 API, POSIX API, and Java API
return value
BOOL ReadFile c (HANDLE file,
LPVOID buffer,
DWORD bytes To Read,
LPDWORD bytes Read,
LPOVERLAPPED ovl);
parameters
function name
Fig. 2.3 The API for the ReadFile() function
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2.3 System Calls
System-call interface
user application
open()
user mode
system call interface
kernel mode .
open()
Implementation of
open() system call …
return i .
Fig.2.4 The handling of a user application invoking the open() system call
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2.4 Types of System Calls
Windows
Unix
Process Control
CreateProcess()
fork()
ExitProcess()
exit()
WaitForSingleObject()
wait()
File Manipulation
CreateFile()
open()
ReadFile()
read()
WriteFile()
write()
CloseHandle()
close()
Device Manipulation
SetConsoleMode()
ioctl()
ReadConsole()
WriteConsole()
Information Maintenance
GetCurrentProcessID()
getpid()
SetTimer()
alarm()
Sleep()
sleep()
Communication
CreatePipe()
pipe()
CreateFileMapping()
shmget()
MapViewOfFile()
mmap()
Protection
SetFileSecurity()
chmod()
InitlializeSecurityDescriptor()
umask()
SetSecurityDescriptorGroup()
chown()
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2.5 System Programs
File management
-create, delete, copy, rename, print, dump, list, and generally manipulate files and directories
Status information
-ask data, time, memory, disk, and user and such information
File modification
-create, modify and search the contents of the files
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2.5 System Programs
File management
-create, delete, copy, rename, print, dump, list, and generally manipulate files and directories
Status information
-ask data, time, memory, disk, and user and such information
File modification
-create, modify and search the contents of the files
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2.5 System Programs
Programming-language support
-compilers, assemblers, debuggers and interpreters
Program loading and execution
-absolute loaders, relocatable loaders, linkage editors and overlay loaders
Communications
-create virtual connections among processes, users, and computer systems.
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2.6 Operating-System Design
and Implementation
Design Goals
Mechanisms and Policies
Implementation
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14. 2.7 Operating-System Structure
Simple Structure
Application program
Resident system program
MS-DOS device drivers
Application program
Fig. 2.5 MS-DOS layer structure
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15. 2.7 Operating-System Structure
Layered Approach
layer N
user interface
layer 1
layer 0
hardware
Fig. 2.6 A layered operating system
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16. 2.7 Operating-System Structure
Microkernels
-Mach: remove all nonessential components from the kernel and implement them as system and user-level programs.
-provide a communication facility between the client program and the various services that are also running in user space.
-easy to extend the operating system
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17. 2.7 Operating-System Structure
Modules
scheduling classes
device and bus drivers
file systems
Core Solaris kernel
miscellaneous modules
loadable system call
STREAMS modules
executable formats
Fig. 2.7 Solaris loadable modules
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18. 2.10 Operating-System Generation
An operating system is designed to run on any of a class of machines at a variety of sites with a variety of peripheral configurations.
SYSGEN(system generation)
-reads from a given file, or ask for information.
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2.11 System Boot
Bootstrap program/loader
-a small piece of code which locates the kernel and loads it into main memory, and starts its execution.
1.Powered up
2.IR load a predefined location
3.Bootstrap perform a variety of tasks(diagnostics)
4.Start the operating system
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