Advances in Operating System Design CS 60038 17614

1
Advances in Operating System Design (CS 60038 /
17614)

• Program vs. Job vs. Process/Task vs. Thread .
• Process Management Synchronization Issues.
• Memory Management Virtual Memory.
• I/O (Peripheral) Devices Management.
• File System Management.

2
Brief Reviews of basic concept

• Role of an Operating System.
• Structural Hierarchical overviews of a typical
  Computer System along with System Software
  Layers.
• Evolution of the Operating System.

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Role of an Operating System

• General Views.
• Users Views.
• System Designers Views.

4
Role of an Operating System (General Views)

• A piece of Software that helps a computer system
  to operate ( A System Software).
• The Monitor program that monitors all activities
  going on inside the Computer .
• A Resource Manager.
• The Man Machine Interface.

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Role of an Operating System (Users View)

• Accepts commands that make a Computer
  act/operate (Input, Store, Process, Output).
• Shields the basic limitations of the Computers
  resources from the user.
• Guarantees Response time for each user command.
• Provides a hospitable user friendly interface.

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Role of an Operating System(System Designers
View) - 1

• Develop Device Drivers.
• Provide Utility Services like Editors ,
  Translators other Applications.
• Effective Utilization Management of System
  Resources.
• Frame a Friendly ( Self explanatory Self
  Correcting) user interface.

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Role of an Operating System (System
Designer View) - 2

• A. Device Driver Programs Helps the devices
  to function.
• The basic devices that should Operate
• Key board Read.
• Mouse Click.
• V.D.U. Display.
• Disk (Magnetic CD) Read Write.

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Role of an Operating System(System Designers
View) - 3

• Basic Features of Device Drivers
• Written using Low Level / Low level Features of
  a programming language.
• Underlying machine / CPU dependent.
• Contained in non-volatile ROMs and / or loaded
  from disk(s) on demand (if installed).
• Makes the peripheral interfaces to interact with
  the CPU in accordance with O.S. Commands.

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Role of an Operating System (System
Designer View) - 4

• B. Processor /Process Management
• Involves the following tasks
• 1) Managing the single CPU and its
  co-processors like Floating Point Units (FPUs)
  Multi Media (MMX), Memory Management Units
  (MMUs ) Normally handled directly by
  Architecture.
• 2) Coordinating Several CPUs in a Multiprocessor
  System which may be
• a) Tightly Coupled.
• b) Loosely Coupled. (Distributed).

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Role of an Operating System (System
Designer View) - 5

• C. Memory Management
• - Cache (ON Chip OFF Chip) Normally
  handled by Architecture .
• Main or Primary Memory.
• Secondary Storage Disk (Hard,Floppy) /
  CDs /Tape ( To provide virtual storage ).

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Role of an Operating System (System
Designer View) - 6

• Managing the File System (Information Bank).
• Management Control of the peripheral
  Devices associated Interfaces.
• Role of the Interfaces
• a) Matching Electrical Characteristics.
• b) Matching Speeds.

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Processor Management Functions

• Allocate / De-allocate jobs (processes) to
  processors
• (in accordance with predefined policy).
• Keep track of current status of each process
• as well as the processor(s) .
• Decide on the processor(s) occupancy
  period(s).
• Ensure guaranteed response time.
• Report any illegal operation(s) and take
  corrective
• actions.

13
Memory System Management Functions

• Keeping track of memory occupancy.
• (what process resides where and how much)
• Swapping in / out portions of a process
  between main memory secondary storage on
  requirement.
• Ensure availability of enough memory in a
  manner transparent to the user.
• Create the feeling of the existence of an
  infinite sized , high speed memory for any
  process.

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FILE Management Functions

• A function which is mostly used by the users.
• Keeping track of the Secondary Storage (File
  Cabinet) .
• (which file stored where the directory
  structure)
• Storage / (Allocation space) for files.
  space
• De-allocating space for deleted files .
  management
• Compacting freed space on disk.
• Accessibility control protection (Read,
  Write, Execute Access) of files.
• Forms the backbone of any Data Base and / or
  Information System.

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Peripheral Device Management Functions

• Installation of device drivers.
• Activating device driver programs on
  demand (usually user request).
• Allowing the fast paced CPU and the slow paced
  / faster peripheral interface to operate at
  their
• own speed.
• Guaranteeing availability of peripherals to all
  requesting processes without sacrificing
  response time.
• Enforce proper device sharing protocols if
  needed (to make non shareable devices shareable)
• Monitoring each active device status.

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The O.S. System Hierarchy
Command Line Interpreter
Command Line Interpreter
Kernel / Device Drivers
GUI
H/W
E D I T O R
Graphics User Interface (GUI)
User Programs
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Evolution of Operating System

• Serial .
• Simple Batch.
• Multi programmed Batch.
• Time Sharing/ Multi Tasking.
• Multi Processing ( Parallel Distributed).