Lecture 2 - Operating Systems

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Objectives

• Introduce students to systems software, operating systems functions, the file systems available in Windows, and Windows XP.

Contents

• Application Software
• System Software
  • BIOS and ROM
  • Operating System
  • Command based OS vs Graphical OS
  • Some Typical Operating Systems
• Windows File Systems
  • FAT
  • NTFS
• The PC Network
  • Network Components
  • Protea
  • Home Directory (H:)
  • Disks
  • Other PC Labs
• Windows XP
  • Control Panel
  • Clipboard
  • Windows File System
  • Windows Explorer
  • Windows XP Profiles
  • Changing Passwords
  • Logging off
• Security
• Anti-Virus Software
• The Unix Network
• Student Information
• What's Next
• Key Points
• Further Reading

*** These are the last lecture notes to be handed out in class.

*** It is up to you to print them in the future.

*** Tutorials start later today

1. Application Software

• Programs such as Microsoft Word, Excel etc.
• Require a base to perform on, called the Operating System

2. System Software

The software base of a computer that application programs use to access hardware functions. e.g.:

• Word prints to the screen or a printer via the system software.
• Word reads from the keyboard via the system software.

There are two main levels of system software; BIOS and Operating System.

2.1 BIOS ROM

• A special ROM (Read Only Memory) chip called the BIOS (Basic Input Output System)
• It contains programs to get the system up and running and includes programs for hardware devices to run and communicate

2.2 Operating System (OS)

A series of programs to perform certain functions.

Low level functions loaded on boot-up:

• Read from/write to disks
• Allocate memory to programs
• Virtual memory management
• Multitasking support
• Network communications
• Input/output support
• System security
• Provide screen drawing (user interface) commands for programs

Higher level functions usually exist as separate programs (utilities):

• Provide initial user interface
• Disk/file management
• Monitor system performance
• Editor to enable changes to configuration settings
• Network administration/connections

OS's are read from disk
Starting up an OS is called BOOTING-UP

On the LTUB PC network we use two main OS's:

• Windows XP - The local OS on each workstation
• Windows Server 2003 - Used to provide the networking capabilities on our system

2.3 Command Based OS vs Graphical OS

• An OS performs a series of tasks, usually initiated by a user
• Command based OSs
  • Have a limited vocabulary of commands.
  • Unusable if do not know the commands and their syntax
    e.g. copy   A:\afile.ext   C:\asubdir\newname.doc
  • Generally command line interfaces are faster for expert users
  • Examples of command based OSs are DOS and UNIX
• Graphical OSs
  • Commands are selected via pull-down menus
  • Graphical interfaces are better for novices
  • Examples of graphical OSs are Windows and MacOS
  • X-Windows (on Unix) is a graphical interface for UNIX

2.4 Some Typical Operating Systems

• MS Windows - Windows XP
• Mac OS X
• UNIX
  • Unix has many variants, including Linux

3. Windows File Systems

3.1 FAT

• The original single-user OS for IBM PCs (MS DOS) introduced by Bill Gates in 1982 used a file system known as FAT (File Allocation Table)
• FAT was designed for small disks and is very restrictive
• FAT32 was introduced to help remedy some of the restrictions
• Windows 98/ME still use the FAT or FAT32 file systems
• Floppy disks and USB memory/keys use FAT32

3.2 NTFS

Windows XP/2000/NT use NTFS (New Technology File System) and still supports FAT.

NTFS provides:

• Better recovery after system failure
• Ability to handle extremely large storage media
• Security features, such as execute-only files
• Unicode filenames
• Future extensibility
• From a user's perspective NTFS operates exactly as FAT file systems

4. The PC Network

This is the main PC based network.

• System Administrator is Andrew Swan of DSSG (Desktop Systems Support Group)
• The network cannot be accessed from outside of the University
• Mainly used for word processing, web browsing, and for some software development etc.

4.1 Network Components

Servers

• The server uses Windows Server as the networking/file management software
• The file server is located in the Westy Williams Computing Centre (DSSG/ITS) which is near the MacKay Lecture Theatre
• The email server is located at Bundoora

PCs

• The PCs (client) use MS Windows Professional XP as the operating system
• Each group of PCs is on a subnetwork (subnet). The PCs within a subnet typically communicate at a maximum of 100Mb/s (mega bits per second)
• There are a number of PC labs. We will be using Computer Lab 1 (B1.54) and Computer Lab 2 (B1.53) located in the Business Building for tutorials. (other PC labs are located in Applied Science 2, Health Sciences and Applied Science 1)
• Most staff on the campus are also connected to the PC network
• Student accounts are limited to 50 MB each

Software

Most PCs will have the following software loaded locally (and more):

• MS Windows XP Pro
• MS Office 2003
• Macromedia
• Web Browsers
• Miscellaneous
• Development Software

Printers

• There are a number of printers located around the campus. Most labs will have a printer.
• Before you can print you need to register for a La Trobe Transact account and add money to the account. You can register at the Library.
• Money can be added to your account at reload stations located in the Library and the Business building. Follow the instructions on the small display located on the front of the machine.
• To print to the printer in the current lab select File > Print.
• Different printers can be selected from within applications at the Print dialogue box (File > Print).
• Before the job is printed. a dialog box is displayed showing, the job (the name of the file to be printed), the cost, number of pages and the printer it is to go to. Click on the Print button in the dialog box to print or the Cancel button if you decide not to print. If you click the Print button and there isn't enough in you Transact account you will be informed of this and the print job will be cancelled automatically.
• You can find out your current account balance when you print or from reload stations or photocopiers or on-line.
• You can check transactions and your account balance on-line at:
  http://cg-websrv.commfac.latrobe.edu.au/transact/transact_student.php
• Printing costs 11c per sheet.
• See the La Trobe Transact web page for more information on printing.

4.2 Protea

• Is the main student server on the La Trobe Bendigo network
  • PC compatible
  • Pentium 4
  • 1 GB RAM
  • Hard disks - 1+ terabyte RAID
• Hard disk stores students' data files
• Approximately 6000 accounts
• Backups are performed daily
• Access to accounts is controlled by a domain controller (server) located at Bundoora. This allows students to access their accounts from most labs in the university.

4.3 Home Directory (H:)

Each student has a directory referred to as My Home Drive (H:). This is the only directory that you can save files to. Files are stored on the server - not the PC you are working on. A maximum of 50MB can be saved to your account. Don't save to the C: drive as the work will be lost. Don't save large files (e.g. pictures) to your desktop as these take up space as well.

4.4 Drives

The hard drive on the PCs is divided into a number of partitions (sections). Typically the hard drive will be partitioned into C: and D: drives. Each partition has a particular purpose. Most PCs will have the following local drives.

USB drives/memory may be used but should not be larger than 512KB. The system Administrator is notified if larger drives are used.

4.5 Other PC Labs

• There are other PC labs in Applied Science 2 and Health Sciences. You can use these computers as you would the PCs in the labs in the Business building.
• The Study Hall is a PC lab that doesn't have scheduled classes in it, it is mainly used for email, web browsing and word processing. It may not have all of the software found in the other PC labs.

5. Windows XP

Graphically based OS.

The Windows OS provide the functions:

• Disk access
• Memory management
• Screen drawing (graphical) functions (for all programmers to use - through the API)
• CPU time sharing - multitasking
• Organises swap file (Virtual memory - disk paging) to extend RAM
  • RAM can seemingly be expanded by using some of a hard disk to act as extra 'main memory'
  • Allows running of larger programs, or more programs can be loaded into memory at the one time
  • May slow performance
  • Size set in Windows Control Panel
• Windows XP itself, requires about 128MB RAM to run in, and about 192MB RAM to do anything useful

Windows XP has a number of utilities:

5.1 Control Panel

For setting-up the windows environment:

• colour schemes
• hardware settings - display, network, cache, drivers for sound, etc.
• time/date
• printers
• modems

The control panel is disabled on LTUBs PC networks.

5.2 Clipboard

• Temporary storage (buffer) area in Windows.
• Common to all running programs.
• Accessed via cut/copy/paste

5.3 Windows File System

• Hierarchical (tree) file system.
• Best viewed with Windows Explorer

5.4 Windows Explorer

• Windows Explorer is used to manipulate and manage the storage of files
• Can be run by right mouse clicking on the Start button and selecting Explore
• Windows Explorer's window is divided into two:
  • Left side displays directory structure
  • Right side shows files and folders in current directory
• Create new folders - but only within folders you have write access to
• Delete files, folders and whole folder trees!
• Copy or Move files around:
  • Copy or Cut then move to a new folder and Paste
  • or simply drag and drop from one folder to another
• Select a drive
• Select a different computer if on a network
• Shows disk space used by selected files and disk space free on current drive
• Can select files (Hold CTRL and SHIFT keys down to select multiple files)
• Easy to Copy/Move files
• Can also Run a program by double-clicking on the filename

Path

• When an OS searches for a file it doesn't search the entire disk.
• Searches only in the directories named in the path.
• Two special directories (these can be seen when doing a dir command at the DOS Command Prompt):
  • .       (dot) - current directory
  • ..      (double dot) - parent directory

e.g. the path may be defined as something like:

PATH=C:\WINNT; C:\WINNT\SYSTEM32; C:\WINNT\SYSTEM ;X: ;Z:

In Windows XP the path can be set under Systems Variables in Environment Variables:

Control Panel > Systems > Advanced > Environment Variables

5.5 Windows XP Profiles

Each user has their own profile in Windows XP which is the storage of information about:

• Taskbar Start Menu program applications
• Programs the user has used
  • Registration can take a long time the first time you use a program
• Desktop layout, such as colour schemes, desktop application icons, etc.
• Previously used document list
• Security information, such as access to common program groups or network printers - set by the Network Administrator.
• Your profile is kept in your account
• This profile is copied into your workstation's profiles directory when you login, then copied back when you logoff.

5.6 Changing Passwords

To change you password on the PC network:

1. Press Ctrl+Alt+Delete (all at once)
2. Click the Change Password... button.
3. Type your Old Password (existing password)
4. Type your New Password twice. (Passwords must contain at least 8 characters)

5.7 Logging Off

To logoff  the PC network:

1. Select Start > Log Off
2. Click the Log Off... button

6. Security

Windows Server and Windows XP look after security, involving:

• Restricted access - need username and password
• Restricted read/write permissions to different parts of the disk
• Permissions to print
• Disk space allocation

7. Anti-virus Software

• Sophos antivirus software is used on the PCs

8. The UNIX Network

• The System Administrator is Howard Cock (h.cock@latrobe.edu.au) located in the Business building (room B1.07). See Howard with problems regarding the UNIX network only.
• Mainly used in programming subjects
• The main UNIX lab that we will be using is room B1.11 (PCs). The other UNIX lab is 1.08 (Macs)
• We will look at the UNIX Operating Systems in some detail later in the semester

Servers

There are two main servers, redgum for student use and ironbark for staff. Both of these will soon be Apple Xserve UNIX servers.

redgum & ironbark

• Apple Xserve (these act as UNIX servers to any UNIX workstation, whether they be PCs, Macs,...)
• Dual G5 processors
• 2GB RAM
• Total disk capacity is in terabytes (1000's of gigabytes)
• 6000 student accounts
• Disk space limited to 50MB per student account
• Backed up to hard disk nightly (the main purpose of this is to restore the system is there is a major failure - not to restore files accidentally deleted by students)

Workstations

The UNIX workstations we will be using in this subject are located in lab B1.11 (Computer Lab 3, also known as itlab3) are networked into redgum's disk drive where your files are stored. The CS & CE Department has a number of different types of UNIX workstations, running different flavours of UNIX.

• 24 Dell IBM compatible workstations (We will be using these later in the subject)
  • Operating System: Linux
  • Hardware: 2GB RAM, Intel processors, 19in monitors, DVD burners
  • Named indya, indyb, ...
  • Room B1.11
• 24 Apple iMacs
  • Operating System: Mac OS X
  • Hardware: 2GB RAM, Intel Core 2 Duo processors, 20in monitors, DVD burners
  • Room B1.08

Inappropriate use of the DVD burners will result in loss of computing facilities and students will face disciplinary action.

DVD burners are to be used for work legitimately associated with University subjects; NOT for movies, pictures etc.

Logging On

We won't be using the UNIX labs for some weeks, however if you wish you can use them. Your account should already be created for you, even if you haven't used it before. Usernames and password on UNIX are case sensitive, you must type them exactly as specified.

• login username = first 8 characters of the username listed on your Statement of Enrolment form
• password = initially the same as on your Statement of Enrolment form. If this doesn't work try your student on-line password.

9. Student Information

Information for current students of the university can be found at:

• Latrobe University home page: http://www.latrobe.edu.au/ and click on the For Current Students link or
• http://www.latrobe.edu.au/students/

Information on computer accounts, computer labs, passwords, email, IT Services (info on email, proxy information for dialling in to the Uni, ...),  timetables etc can be found on this page. Most of the computing related links are under the headings University Services.

What's Next?

• For the next 7 weeks we will commence looking at Software Development
• This includes problem solving and programming
• No programming background is assumed

Key Points

• The two main categories of software are Application Software and System Software
• System Software includes BIOS and Operating Systems
• Operating Systems provide the basic functionality of a system
• The two main types of Operating Systems (OS) are command and graphical based
• UNIX is an example of a command based OS and Windows XP is an example of a graphically based OS
• Windows has three types of file systems: FAT, FAT32 and NTFS. NTFS is the most sophisticated
• Windows XP is a single user OS that is considerably more sophisticated than its predecessors
• Windows Server and Windows XP provide security for your account

Further Reading

• Bott, E. & Siechert, C. (2001) Microsoft Windows XP Inside Out. Redmond, Washington: Microsoft Press.
• Pogue, D., Zacker, C and Zacker L. (2003) Windows XP Professional Edition: The Missing Manual. Sebastopol, CA: O'Reilly.
• Taylor, D. (2005) Sams Teach Yourself UNIX in 24 Hours. 4th ed. Indianapolis, Indiana: Sams.

Written by Tim Whitfort.