LINUX System : Lecture 7

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LINUX System Lecture 7

• Bong-Soo Sohn

Lecture notes acknowledgement The design of
UNIX Operating System
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Architecture of the UNIX
user programs
libraries
trap
user Level kernel Level
system call interface
file subsystem
buffer cache
hardware control
hardware
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System calls Libraries
user programs
libraries
trap
user Level kernel Level
system call interface
system call interface
file subsystem
buffer cache
hardware control
hardware
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System calls Libraries

• System call library
• OS service in the form of C function call
• Standard library, User library
• Linked with the programs at compile time and are
  part of the user program

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File Subsystem (1)
user programs
libraries
trap
user Level kernel Level
system call interface
file subsystem
buffer cache
hardware control
hardware
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File Subsystem (2)

• Managing files and structures of file system
• Allocating file space
• Administering free space
• Controlling access to files
• Retrieving data for users
• Interact with set of system calls
• open, close, read, write, state, chown, chmod

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Buffering Mechanism (1)
user programs
libraries
trap
user Level kernel Level
system call interface
file subsystem
buffer cache
hardware control
hardware
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Buffering Mechanism (2)

• Interact with block I/O device drivers to
  initiate data transfer to and from kernel.

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Process Control Subsystem (1)
user programs
libraries
trap
user Level kernel Level
system call interface
file subsystem
buffer cache
hardware control
hardware
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Process Control Subsystem (2)

• Managing process structures (proc table, u
  table,)
• Process scheduling
• Interprocess communication (IPC)
• Memory management
• Responsible for process synchronization.
• Communicate with file subsystem
• Loading a file into memory for execution
• Interact with set of system calls
• fork, exec, exit, wait, brk, signal

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Process Control Subsystem (3)

• Memory management module
• Control the allocation of memory to a process
• Scheduler module
• Allocate the CPU to processes
• Interprocess communication
• There are several forms.

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Hardware Control (1)
user programs
libraries
trap
user Level kernel Level
system call interface
file subsystem
buffer cache
hardware control
hardware
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Hardware Control (2)

• Responsible for handling interrupts and for
  communicating with the machine.
• Devices such as disks or terminals may interrupt
  the CPU while a process is executing

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Topics to be covered

• File subsystem
• Process control subsystem
• (Memory Management)
• Signal
• IPC (Inter-Process Communication),
  Synchronization
• UNIX System Programming (System Calls)

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Reference Books

• The design of the UNIX Operating System, M. J.
  Bach
• UNIX Internals The New Frontiers, U. Vahalia
• Advanced Programming in the Unix Environment, 2nd
  Edition, W. R. Stevens, S. A. Rago