Chapter 18 Three Operating Systems

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Chapter 18Three Operating Systems

• The Architecture of Computer Hardware and Systems
  Software An Information Technology Approach
• 3rd Edition, Irv Englander
• John Wiley and Sons ?2003

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Three Operating Systems

• Microsoft Windows 2000/XP
• UNIX and Linux
• IBM zSeries z/OS

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Microsoft Windows 2000/XP

• Design Goals
• Operating System Features
• User Environment
• Desktop Components
• Windows 2000/XP Architecture
• Overview
• System Block Diagram
• Logical Memory Map

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Design Goals

• Extensibility
• Object-based modular design
• Portability
• Written in C and C to facilitate porting to
  other CPUs
• Reliability
• Kernel architecture design to protect from
  internal errors and buggy application programs
• Downward compatibility
• Compatible with earlier versions of Windows and
  DOS
• Scalability and Performance
• Supports symmetric multiprocessing

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Operating System Features

• Single user 32-bit or 64-bit, pre-emptive
  multi-tasking operating system
• Powerful GUI that behaves consistently for local,
  network, and Internet use
• Support for new capabilities
• Multimedia, plug-and-play hardware, electrical
  power conservation
• Manageable and secure file system with built-in
  recoverability options and is downwardly
  compatible
• API that provides a wide range of services to
  simplify application development and ensure
  consistency
• Built-in networking and a new distributed file
  system
• Network server capabilities

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User Environment

• Simple for novice, powerful for advanced user
• Tools, operations and applications that use the
  API behave in a consistent manner
• Extensive context-sensitive help
• Users system parameters are modifiable
• Applications and users have access to the same
  services and interface features
• Tools and operations perform reasonably and in an
  intuitive manner

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Desktop Components
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Windows 2000/XP Architecture

• Modified microkernel-based
• User mode
• Environmental subsystems
• Expose OS services to the user through an API
• System support processes
• Logon and user session management
• Server processes
• Protected (kernel) mode
• Hardware abstraction layer
• Kernel
• Executive layer

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Executive Layer

• Object manager
• Provides standardized interface for objects
• Process manager
• Virtual memory manager
• I/O manager
• Security reference monitor
• All protected objects are monitored
• Enforces validation procedures and audits
• Local Procedure Call (LPC)
• Control of all service requests and interprocess
  activities
• Windowing and Graphics System
• Manages Windows graphics
• Provides Windows screen interface tools

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Overview of Windows 2000
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System Block Diagram
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Logical Memory Map
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UNIX and Linux

• Design Goals
• Pioneering Design Features
• Operating System Features
• User Environment
• General Organization
• Kernel operations

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Design Goals

• Easy-to-use, interactive, powerful, and flexible
  interface
• Powerful programming tools
• Compilers and associated tools
• Use of small, simple utility programs to perform
  tasks and to construct more complex applications
• Small and simple kernel together with a separate
  interface shell
• Logical file system
• Multi-tasking and multiuser capabilities
• Simple system portability

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Pioneering OS Design Features

• Process creation and control
• Separate shell for user interface
• Hierarchical directory file system
• Ability to combine small independent software
  modules to accomplish a more complex task

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Operating System Features

• Preemptive multitasking with multiuser
  capability, automatic scheduling, and background
  execution
• User shells that provide an interactive
  interface, commands, and programming tools
• Interactive process creation and management
• Hierarchical, tree-based file system
• Kernel
• Network administration tools

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User Environment

• Login
• User name and password
• Start-up file for user environment customizations
• System, group, and user protections are set
• Interface shells
• Bourne shell, C shell, and Korn shell are the
  most commonly used
• Command line prompt
• X-Windows interface
• Logins to remote UNIX computers

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General Organization of a UNIX System
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Kernel Operations

• Virtual storage and memory management
• Process management
• File management
• I/O management
• Networking and communication

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Virtual Address Space for a Process
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IBM zSeries z/OS

• Design Goals
• Operating System Services
• User Environment
• User Interfaces
• MVS Organization
• Virtual Memory Map for a Task
• Data Management

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Design Goals

• Maximize system performance and availability
• Maximize amount of processing by providing
  support for execution of batch programs
• Minimize operator support effort
• Reliability
• Security

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Virtual File System vs.Socket Layered Structure
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Operating System Services

• Sophisticated resource allocation services and
  workload management
• Data set management services
• Job and task management
• Virtual storage operation and management
• Network services
• Time-sharing support
• System resource logging, auditing and accounting
• Error detection, recovery, and logging
• Reassignment of tasks and data to other resources
  in the event of an error or failure
• System support programs and facilities
• Security services
• Large-scale cluster support

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User Environment

• BCP, Base Control Program
• JCL, Job Control Language
• TSO, Time Sharing Option
• Used for program development and job preparation
• JES, Job Entry Subsystem
• Job submissions
• ISPF, Interactive System Productivity Facility
• Menu-driven facility that serves as an extension
  to TSO
• CICS, Customer Information Control System
• Application enabler that provides services to
  application programs that have been developed to
  work with it
• UNIX

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User Interfaces
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MVS Organization
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Virtual Memory Map for a Task
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Data Management

• Data sets
• z/OS files
• Sequential, random, or indexed sequential access
• Fixed or variable size
• Partitioned
• Directory
• Members - group of independent, related records
• Catalogs
• z/OS directories
• Master catalog for the system
• VTOC catalog for a DASD (disk) device
• User catalog has an indexed entry in the master
  catalog

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Steps in Location of a Data Set