Pertemuan 3 Konsep Sistem Operasi

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Pertemuan 3Konsep Sistem Operasi

• Matakuliah T0316/sistem Operasi
• Tahun 2005
• Versi/Revisi 5

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Learning Outcomes

• Pada akhir pertemuan ini, diharapkan mahasiswa
• akan mampu
• menjelaskan istilah dan konsep sistem operasi (C2)

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Outline Materi

• Konsep
• Processes
• Deadlock
• Memory management
• I/O
• File
• Shell
• System call

• Struktur
• Monolithic
• Layered
• Virtual machine
• Exokernels
• Client-Server

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²          OPERATING SYSTEM CONCEPT
 Process -     Program in execution -    
Consist of o    Executable program, data,
stack o    Program counter, stack pointer,
registers -     Process table ? array or linked
list of structure of the process in
execution -     Process has o    Address space
(core image) o   Attribute/information in the
process table
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-     A process tree
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Deadlock
-     Condition in which interacting process
cannot be continued and there is no process that
can get out of that condition.
(a) A potential deadlock. (b) an actual deadlock.
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Memory Management -     Multiple program dalam
memory ? needs o    Protection o    Address
space management
Input/Output -     Independent I/O
software -    Device dependent, eg. device
drivers
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      Files -     Directory   -    
Pathname -     Protection mode ? rwx bits -    
File descriptor
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-     Mounted file system
-     Special file o    Block o    Character  
-     Pipe
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      Security -     Protection, eg. rwx
bits -     Intruders, from human or non-human
(eg. virus)
       Shell -     Unix command
interpreter -     Prompt
Example date date gt file sort lt file1 gt
file2 cat file1 file2 file3 sort gt
/dev/lp cat file1 file2 file3 sort gt /dev/lp
-    Background job
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      SYSTEM CALLS
Interface between user program and operating
system
Steps in Making a System Call
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• -    Example of system calls
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• o    Process Management

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o    File Management
o   Directory and file system management
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o    Miscellaneous
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²          OPERATING SYSTEM STRUCTURE
Monolithic system -     The big mess -    No
structure  
Simple structuring model
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Layered System -     Hierarchical layer, each
layer is built on top of the layer below it.
-    Eg THE system
  Generalisation of layering concept at MULTICS ?
concentric ring
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Virtual Machine -     Virtual machine monitor ?
not an extended machine, but an exact copy of the
bare hardware -    CMS (Conversational Monitor
System)  -   JVM (Java Virtual Machine)
Structure of VM/370 with CMS
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Exokernels -     Designed for a system that gives
each user clone of the actual computer, but with
a subset of resources -    Program run on the
bottom layer to allocate resources to virtual
machine
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Client-server model -     Mikrokernel -    
Client process -     Server process -   
Mechanism vs policy

The client-server model
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The client-server model in a distributed system
 Advantages of distributed system model -    
Smaller parts are easier to maintain -     No
direct access toward hardware -    Adaptability