Transcript Inside and Outside the OS

Chapter 14
The User View of Operating Systems
The Architecture of Computer Hardware
and Systems Software:
An Information Technology Approach
3rd Edition, Irv Englander
John Wiley and Sons 2003
Wilson Wong, Bentley College
Linda Senne, Bentley College
User Interface
 Help the user use the computer system
productively
 Provide consistent user interface
services to application programs to
lower learning curves and increase
productivity
 Choice of user interface depends on the
kind of user
 Writing programs vs. running applications
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User Functions
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Program execution
File commands
Mount and unmount devices
Printer spooling
Security
Inter-user communication
System Status
Program Services
 DCOM, CORBA, Remote Procedure Call (RPC)
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Interface Design
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CLI - Command Line Interface
Batch System Commands
Menu-Driven Interfaces
GUI - Graphical User Interface
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Command Line Interface
 command <operand1> <operand2> …
<switch1> <switch2> …
 Operands
 keyword (switches) and/or positional
 Advantages
 More flexible and powerful
 Faster for experienced users
 Can combine commands
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Command Line Interfaces
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Command Languages
 Provide a mechanism to combine sequences of
commands together. These pseudo-programs are
known as scripts or batch files.
 Startup files – OS configuration, user preferences
 Features of Command Languages
 Can accept input from the user and can output messages to
I/O devices
 Provide ability to create and manipulate variables
 Include the ability to branch and loop
 Ability to specify arguments to the program command and to
transfer those arguments to variables within the program
 Provide error detection and recovery
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DOS Batch File
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UNIX Shell Script
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Menu-Driven Interface
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No need to memorize commands
All available commands are listed
Menus can be nested
Low data requirements
Still used in many ATM and Point-ofSale systems
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Menu Driven Interface
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Windows Interfaces
 Also known as Graphical User
Interfaces (GUIs)
 Mouse-driven and icon-based
 Windows
 Are allocated to the use of a particular
program or process
 Contain a title bar, menu bar, and widgets
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GUI Interface – Windows XP
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GUI Interface – Linux KDE
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GUI Interface - MacIntosh
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GUI vs. CLI
GUI
 Advantages
 Easy to learn and use
 Little training
 Amenable to multi-tasking
 Disadvantages
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Harder to implement
More HW/SW requirements
Requires lots of memory
SW is complex and difficult
to write
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CLI
 Advantages
 More flexible and powerful
 Faster for experienced
users
 Can combine commands
 Disadvantages
 More difficult to learn and
use
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X-Windows
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Duocentric Interface
 Focus on the document rather than the
application being executed
 Expand role of OS by moving
capabilities from the application to
system services
 Example: click on document to run
program
 Effort to assure that every application
program responds in similar ways to user
actions.
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Copyright 2003 John Wiley & Sons
All rights reserved. Reproduction or translation of this
work beyond that permitted in Section 117 of the 1976
United States Copyright Act without express permission
of the copyright owner is unlawful. Request for further
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Department, John Wiley & Songs, Inc. The purchaser
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by the use of these programs or from the use of the
information contained herein.”
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