Pertemuan 24 Sistem Operasi Unix

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Pertemuan 24Sistem Operasi Unix

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

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Learning Outcomes

• Pada akhir pertemuan ini, diharapkan mahasiswa
• akan mampu
• mendemonstrasikan sistem operasi Linux, dari
  manajemen proses, memory, file sampai dengan I/O
  (C3)

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Outline Materi

• Sejarah Unix
• Overview Unix
• Shell
• Program Utiliti
• Proses pada Unix
• System Call
• System memory dan I/O pada Unix

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LINUX

• Sejarah Unix
• Unics
• PDP 11 Unix
• Portable Unix
• Barkeley Unix
• Standar Unix
• MINIX
• LINUX

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Overview of Unix

• UNIX Goals
• UNIX is an interactive system designed to handle
  multiple processes and multiple users at the same
  time.
• It was designed by programmers, for programmers,
  to use in an environment in which the majority of
  the users are relatively sophisticated and are
  engaged in software development projects
• Extensive facilities to work together

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Interfaces to UNIX

• The layers of a UNIX system.

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UNIX Kernel

• Approximate structure of generic UNIX kernel

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Booting UNIX
cp

• The sequences of processes used to boot some
  systems

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SHELL

• Program Login
• Prompt
• Command
• Argument
• Redirect
• Pipe
• Shell Script
• Background process

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Contoh

• cp src dest
• head 20 file
• ls x.c y.c z.c
• sort lt in gt out
• sort lt in gt temp head 30 lt temp rm temp
• sort lt in head 30
• grep ter .t sort head 20 tail 5 gt foo
• wc l lt a gt B
• sort lt x head

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Program Utiliti

• Manipulasi file dan direktori
• Filter
• Tool untuk pengembangan program
• Text processing
• Sistem administrator
• dll

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UNIX Utility Programs

• A few of the more common UNIX utility programs
  required by POSIX

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Process pada Unix

• Sistem multiprogramming
• Daemonds
• Cron daemonds
• System fork
• Process parent
• PID
• Pohon process
• signal
• Group process
• UID
• Superuser (root)

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System Calls for Process Management

• s is an error code
• pid is a process ID
• residual is the remaining time from the previous
  alarm

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POSIX Shell

• A highly simplified shell

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Implementasi Process

• Process Table (always in memory)
• Parameter scheduling
• Memory map
• Signal
• Etc
• User Structure (only in memory when the program
  is executed)
• Machine registers
• System call state
• File descriptor table
• Accounting
• Stack kernel

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Handling Memory
Process A
Process B

• Process A's virtual address space
• Physical memory
• Process B's virtual address space

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Sharing Files

• Two processes can share a mapped file.

A new file mapped simultaneously into two
processes
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Implementation of memory management

• Swapping
• Tiga hal yang menyebabkan swapping ke disk
• Fork
• BRK (request for memory)
• Stack increase

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Implementation (2)

• Paging in UNIX
• Page daemon
• Core map ? information about the contents of page
  frame

The core map in 4BSD
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Implementation (3)

• Page replacement algorithm ?Two handed clock
• Two pointers
• First, it clear the usage bit at the front end,
  and
• Then, check the usage bit at the back hand
• If two hands are kept close together, then only
  very heavily used pages have their R-bit stay 1
  (after being zero-ed by the front hand)