Operating System Software

1
Operating System Software

• CS 1
• Rick Graziani
• Fall 2006

2
Operating System Software

• Why are operating system software so important?
• Was Windows 95 a breakthrough for PCs? Why?
• Why was Apple shopping for a new operating system
  and why did it decide on Mac OSX?
• Why is Microsoft worried about Linux?

3
What is an operating system (OS)?

• Operating System Software
• Software which manages the overall operation of
  the computer system including
• hardware (CPU, RAM, I/O)
• security
• system interface
• application interface

4
What is an operating system (OS)?
5
What is an operating system (OS)?
6
The Users View
7
(No Transcript)
8
What is an operating system?

• Software files (programs) which are stored on the
  hard disk
• kernel with the internal programs
• external programs
• Supporting Data Files

9
The kernel

• The operating system software file (program)
  which is copied into RAM, usually from the hard
  disk drive, during the boot-up.
• The kernel remains in RAM while the computer is
  on and is in charge of the overall operation of
  the computer system.
• The kernel contains the internal programs for
  the most often used operations like copying
  files.
• kmem (Linux)
• command.exe (Microsoft)

10
The functions of an operating system

• 1. Manages and Interacts with Computer Hardware
• 2. Provides and Manages System Security
• 3. Provides the System Interface
• 4. Provides the Interface for Application
  Software

11
1. Manages and Interacts with Computer Hardware

• Manages the CPU
• - What software programs the
• CPU works on and when
• Manages RAM
• - What is stored in RAM and
• where it is stored
• - Virtual memory
• - OS will send message when
• RAM is full

12
1. Manages and Interacts with Computer Hardware
(continued)

• Provides the interface for storage devices and
  manages how data is stored on those devices
• - in charge of formatting disks
• - creates sectors and clusters
• - creates F.A.T. or V.T.O.C.
• - sends message when disk is
• full or there is some other
• problem with writing data to
• the disk
• - virtual memory
• - CD-ROM, DVD-ROM
• - Flash drive

13
1. Manages and Interacts with Computer Hardware
(continued)

• Provides the Interface for Input and Output
  Devices
• keyboard, mouse, printer,
• device drivers software programs which allow
  the hardware device to be used by the operating
  system and by application software

14
Manages the CPU processing time and priority

• Processing Applications
• multitasking ability of the operating system
  run multiple software programs (only one programs
  gets processed at a time)
• multiprocessing ability of the operating system
  to run multiple software programs at the same
  time
• Number of users with simultaneous access
• multiuser ability of the operating system to
  allow multiple users access to the same computer
  at the same time
• single user the operating system only allows a
  single user at a time access to the computer

15
Multitasking and Multiprocessing
16
Single-user Operating Systems

• Windows XP
• Only one user has access to the computer system
  at a time

17
Multiuser Operating Systems

• Found on mainframes, minicomputers and
  microcomputers
• Terminals or other computers (PCs, Macs)
  connected to the server
• server a computer which processes information
  (CPU and RAM) , stores information (hard disk),
  and/or provides access to peripheral devices
  (printers) for multiple users

18
The OS also plays a part!

• Amount of RAM recognized by the Operating System
• Windows 95 1GB
• Windows 98 1GB
• Windows 98SE 1GB
• Windows ME 1.5GB
• Windows NT 4GB
• Windows 2000 Professional 4GB
• Windows XP Home 4GB
• Windows XP Professional 4GB
• OS X 8GB due to current hardware limitations
• OS 9.x 1.5GB (no single application can utilize
  more than 1GB)
• Linux 64GB

19
Virtual Memory

• Virtual Memory (VM) the ability of the CPU and
  the operating system software to use the hard
  disk drive as additional RAM when needed (safety
  net)
• Good no longer get insufficient memory error
• Bad - performance is very slow when accessing VM
• Solution more RAM

20
Virtual Memory
21
Examples of Multiuser Operating Systems

• Linux/UNIX
• MAC OS X
• Red Hat Linux
• SUN UNIX
• Microsoft NT, 2000
• And many others, mostly on mainframes and
  minicomputers

22
Advantages/Disadvantages of Multiuser Operating
Systems

• Advantages
• Central location for the installation and
  administration of all software and data
• More cost effective - less expensive than
  multiple computers (PCs, Macs)
• Disadvantages
• Single source for possible problems
• Loss of individual user control of their own
  software, data, and peripherals

23
2. Provides and Manages System Security

• Single-user Operating Systems
• minimal security
• user has full authority
• Multiuser Operating Systems
• login and password capability
• protection of users data stored on the servers
  central hard disk drives
• protection and security for software programs

24
3. Provides the System Interface

• System Interface or shell the interface between
  the user and the computer
• Command Line Interface (CLI)
• UNIX, DOS, older OSs
• Graphical User Interface (GUI)
• Macintosh OS, Windows 3.x, Windows 95, Windows
  XP, X-Windows, GNU, GNOME, Sun OS

25
Command Line InterfaceDOS, UNIX, others
26
DOS plus Windows 3.1
27
Windows 95
28
Windows XP
29
Macintosh
30
Mac OS X
31
UNIX with X-Windows
32
4. Provides the Interface for Application
Software

• Operating systems are software
• Operating systems are designed and developed for
  a specific CPU or family of CPUs
• Macintosh OS Motorola 680xx, PowerPC Gx, Intel
• DOS Intel CPUs
• Windows 9x and XP Intel 80386, 80486, and
  Pentium CPUs
• Linux Intel CPUs
• MS NT 2000 Intel CPUs

33
4. Provides the Interface for Application
Software (continued)

• Application software is developed for an
  operating system
• MS Word for Windows XP
• Windows XP
• Intel CPU
• MS Word for the Macintosh
• Macintosh OS X
• Gx CPU or Intel CPU

34
Compatibility

• Question
• Will software developed for one operating system
  work on another? Will MS Word for Macintosh run
  on a PC with Windows XP?
• Answer
• No (unless there is special emulation software or
  hardware). The software must be developed
  separately for each operating system.
• Much of this is beginning to change with MAC
  using the Intel CPU.

35
Order of Development

• 1. The CPU
• 2. Other Hardware Components
• 3. Operating System Software
• 4. Application Software

36
Preemptive Multitasking vs Cooperative
Multitasking

• Cooperative Multitasking
• OS gives CPU processing time to other programs at
  a logical point, usually during idle time
• Preemptive Multitasking
• OS allocates CPU time between the different
  programs based on amount of time and priority of
  the software application

37
Multiprocessing with Multiple CPUs

• Asymmetric Multiprocessing Tasks are assigned
  to a specific CPU and each CPU has its own RAM
  memory
• Symmetric Multiprocessing Tasks are assigned to
  any available CPU and CPUs can share RAM memory

38
Microsoft Windows Operating Systems

• http//www.microsoft.com/windows/default.mspx

39
Microsoft Windows Vista

• http//www.microsoft.com/windowsvista/default.mspx
  

40
Glass and Animations

• Windows are translucent, meaning that it's easier
  to focus on the content of a window rather than
  the window itself.
• This feature (along with other window design
  enhancements on all Windows Vista computers)
  reduces distraction and streamlines your work
  while making windows easier to manage.
• New scalable thumbnails are used throughout
  Windows to show you the actual first page for
  documents, the actual photo for photos, a screen
  capture for videos, and album art for individual
  songs.

41
Windows Sidebar

• Windows Sidebar connects your desktop
  "gadgets"-mini-applications.
• For example your gadgets might include local
  weather, a photo slideshow, a dictionary, news
  headlines.
• Gadgets are organized in an easy-to-use panel-the
  Windows Sidebar-that discreetly docks on the side
  of your Windows desktop.

42
Folders Virtual Folders

• Virtual Folder, which is simply a saved search
  that is instantly run when you open the folder.
• Subsequently, any time you click on this Virtual
  Folder, Windows Vista runs the search and
  provides results almost immediately.

43
Quick Search Box and Column Headers

• The Explorer Quick Search box and Column Header
  controls help you efficiently narrow down large
  selections of data.
• With the Quick Search Box, you can start typing
  the name or the first few letters of any
  displayed property, and the displayed files
  quickly filter down to just the matching terms.
• The dynamic new Column Header drop down menus let
  you easily choose your filter values.

44
Reliability

• Applications written for Windows Vista will keep
  running-with less chance of hanging or becoming
  unresponsive than with earlier versions of
  Windows.
• Windows Vista is measurably more resilient to
  application problems and can recover better from
  problems that do occur.
• Built-in diagnostics can proactively detect
  problems with system components such as hard
  disks, memory, and networks.

45
Security

• Set of parental control features, providing
  powerful tools to help parents monitor, manage,
  and administer their children's computer usage to
  keep them safe.
• User Account Protection which bridges the gap
  between user and administrative privileges by
  allowing you to run applications under a standard
  user account.
• When you need to perform an administrative task,
  such as install software or drivers, Windows
  Vista prompts you to confirm your intentions or
  to provide your credentials.
• Theft or loss of corporate intellectual property
  is an increasing concern for organizations.
• Improved support for data protection at the
  document, file, directory, and machine level.

46
Linux

• http//www.linux.com/
• http//www.linux.org/

47
www.linux.org

• Initially created as a hobby by a young student,
  Linus Torvalds, at the University of Helsinki in
  Finland.
• Linus had an interest in Minix, a small UNIX
  system, and decided to develop a system that
  exceeded the Minix standards.
• He began his work in 1991 when he released
  version 0.02 and worked steadily until 1994 when
  version 1.0 of the Linux Kernel was released.
• The kernel, at the heart of all Linux systems, is
  developed and released under the GNU General
  Public License (GNU's Not Unix!', see recursive
  acronym).

48
www.linux.org

• Its source code is freely available to everyone.
• It is this kernel that forms the base around
  which a Linux operating system is developed.
• There are now literally hundreds of companies and
  organizations and an equal number of individuals
  that have released their own versions of
  operating systems based on the Linux kernel.

49
www.linux.org

• Apart from the fact that it's freely distributed,
  Linux's functionality, adaptability and
  robustness, has made it the main alternative for
  proprietary Unix and Microsoft operating systems.
  
• IBM, Hewlett-Packard and other giants of the
  computing world have embraced Linux and support
  its ongoing development.

50
www.linux.org

• More than a decade after its initial release,
  Linux is being adopted worldwide as a server
  platform primarily.
• Its use as a home and office desktop operating
  system is also on the rise.
• The operating system can also be incorporated
  directly into microchips in a process called
  "embedding" and is increasingly being used this
  way in appliances and devices.

51
Organizing Files and Directories
52
Organizing Files and Directories
53
Operating System Software

• CS 1
• Rick Graziani
• Fall 2006