04/21/23 1

Operating Systems

CIT 1100

04/21/23 2

Operating Systems

Hardware BIOS

Operating System Drivers

Users Applications

Command Line Interface c:\

Graphical User Interface

04/21/23 3

Operating Systems• An operating system (commonly abbreviated to either

OS or O/S) is an interface between hardware and user; – The operating system acts as a host for computing applications

that are run on the machine. As a host, one of the purposes of an operating system is to handle the details of the operation of the hardware.

– This relieves application programs from having to manage these details and makes it easier to write applications.

– Application Programming Interface (API) is an interface defining the ways by which an application program may request services from libraries and/or operating systems

• Almost all computers (including handheld computers, desktop computers, supercomputers, video game consoles) as well as some robots, domestic appliances (dishwashers, washing machines), and portable media players use an operating system of some type.

04/21/23 4

Operating Systems: Microsoft• MS-DOS • Windows 3.1• Windows 95 (aka Windows 4.0)• Windows 98 (aka Windows 4.1)• Windows Millennium Edition • Windows NT 3.1 • Windows NT 3.5 • Windows NT 3.51 • Windows NT 4.0 • Windows 2000 (aka Windows NT 5.0) • Windows XP (aka Windows NT 5.1) (codename: Whistler) • Windows Server 2003 (aka Windows NT 5.2) (codename: Whistler Server) • Windows Fundamentals for Legacy PCs • Windows Vista (aka Windows NT 6.0) (codename: Longhorn) • Windows Home Server • Windows Server 2008 (aka Windows NT 6.0) (codename: Longhorn Server) • Windows 7 (previously codenamed Blackcomb, then Vienna)

04/21/23 5

DOSDisk Operating System

• DOS, short for "Disk Operating System", is a shorthand term for several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995, or until about 2000 if one includes the partially DOS-based Microsoft Windows versions Windows 95, 98, and Me.

04/21/23 6

Operating Systems• DOS is a single-user, single-task operating system with

basic kernel functions that are non-reentrant: only one program at a time can use them. – Once a process calls a service inside of operating system kernel

(system call), it must not be interrupted with another process calling system call, until the first call is finished.

• The DOS kernel provides various functions for programs, like displaying characters on-screen, reading a character from the keyboard, accessing disk files and more.

Operating Systems

• DOS– Command Line interface– Easy to load from a single floppy– Useful in setting up and troubleshooting

Why bother learning DOS?

• Even though DOS as a stand alone operating system has been completely replaced by Windows, the utilities that were available in DOS are still available under Windows.

• As a computer technician you will be expected to have a good understanding of these utilities and how to use them to troubleshoot some system problems.

Why bother learning DOS?

• Many of utilities are still only available in the DOS.– ping– tracert– ipconfig

• One example would be a system that has problem preventing it from booting properly, possible a hard drive problem, or an incorrect system parameter setting. The best way to trouble shoot this sort of problem is to boot the system using the A: drive with a 3 ½” floppy. – There are numerous utility programs available that can be used

to bypass your system hard drive and boot from a CD ROM drive.

04/21/23 10

Operating Systems

Your Name goes here

In the Lab you will create an MS DOS Boot disk to allow you to boot up your system without the hard drive.

The process can be accomplished in one step using a Graphical User Interface

04/21/23 11

Operating SystemsA Graphical User Interface makes it easier to perform certain tasks.

Drop down menus show options that are available.

Check Box buttons simplify optional selections.

To create a Startup disk select

Volume Label fill in prompt

04/21/23 12

Operating Systems

• Creating an MS DOS Boot Disk form the command line. WINDOWS XP– Step one – Open a Command Line

environment from Windows• START RUN “CMD”

04/21/23 13

Operating SystemsDOS Screen in Windows

04/21/23 14

Operating Systems

– Step two -• CD \Windows\Command• Format a: /S• When prompted enter your name in Volume label

04/21/23 15

Operating Systems

• COMMAND INTERPRETER

• When you type in a command and hit <cr> the Command Interpreter tries to locate the command and load it into memory to be executed.

• If the command is invalid the Command Interpreter gives an error message.

04/21/23 16

Operating Systems

• FILE SYSTEM

• The method used by the Operating System to store information on the hard drive is referred to as the File System.

• DOS and Windows uses a Hierarchical file system

• Older operating systems used a flat file system

04/21/23 17

Operating Systems

• Hierarchical File systems– Arrange files in a logical order– Similar to the way a file cabinet is arranged

• Flat File Systems – Arranges files with no concern as to where

they were placed– A huge file cabinet with no drawers or

divisions

04/21/23 18

Operating Systems

• Hierarchical File System

• Arranged like an inverted tree with the highest level referred to as Root.

• Under the Root directory are either other Directories, or Files– Directory stores either other directories or

Files– Files are the actual document saved

04/21/23 19

Operating SystemsBegin with a Hard Drive

Can be though of as a very large file cabinet used to store data.

After Partitioning and Formatting the hard drive it has a Root Directory /

You can now begin storing files in the root directory

04/21/23 20

Operating SystemsUnder the Root Directory you want to create 3 Sub-Directories to store files

The First Directory you name Meetings

The Second Directory you name Letters

The Third Directory you name Memos

Meetings Letters Memos

The fully qualified name would be a:\Meetings

The fully qualified name would be a:\Letters

The fully qualified name would be a:\Memos

Organizing Files and Directories

04/21/23 22

Operating Systems

Meetings

Creating a Sub Directory in DOS

From the Root Directory A:\ MD Meetings

The Command is MD for Make Directory

04/21/23 23

Operating Systems

A Directory as Viewed using a Graphical User Interface.

WINDOWS Refers to a Directory as a Folder

04/21/23 24

Operating SystemsA Directory as Viewed using a Command Line Interface

The command issued to display the contents is DIR entered from the A:\ prompt

04/21/23 25

Operating Systems

The output from the DIR command shows that the Meeting Directory was created on Feb 19

It also shows that there are no files stored in the Meetings Directory

Notice the system prompt Indicates the Drive being used is A:

Also Shows you which Directory you’re currently in \

04/21/23 26

Operating Systems

The output from the DIR command shows that the Meeting Directory was created on Feb 19

Move into the Meetings directory using CD Meetings command

04/21/23 27

Operating Systems

Notice that the system prompt changes to indicate that you are now in the Meetings Directory Directly under Root \MEETINGS

Enter DIR to get a listing of what you have in the Meetings Directory

04/21/23 28

Operating Systems

• Variables

• The system uses variables to store settings that can change from system to system

• There are 2 types of variables used– System Variables– User defined Variables

04/21/23 29

Operating Systems

• System Variables are used to track parameters used by the system

• PATH Variable is used by the command interpreter to indicate where it should look for executable files.– PATH = C:\Windows\system; C:\Windows

04/21/23 30

Operating Systems

• User Defined System Variables

• Defining a System Variable– SET Name = “Mary”

• Displaying a System Variable– Echo %name%

• Working with System Variables– Echo My Name is %name%

04/21/23 31

PATH

C:\Documents and Settings\tonychen. >pathPATH=C:\Program Files\ThinkPad\Utilities;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\Program Files\Intel\Wireless\Bin\;C:\Program Files\PC-Doctor for Windows\;C:\WINDOWS\Downloaded ProgramFiles;C:\IBMTOOLS\Python22

The above Path Variable tells the command interpreter to look in the following directories:

04/21/23 32

SETTry the following in a DOS environment –

• To see how your PATH variable is set in DOS

echo %path% • To see all the system variable that have been set in DOS

Set • To see how any single system variable is set enter

echo %system variable% Use the command echo and surround the system variable with “%”

• To set up a system variable set variable=value

• Example of setting a system variable set Name=”Mary”

• To see the variable echo My name is

%name%

04/21/23 33

Other DOS commandsHelpTreeDirXcopyShutdown……

34

Operating System Software

35

Manages the Hardware

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

36

Manages and Interacts with Computer Hardware

• 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

04/21/23 37

Windows Properties

04/21/23 38

Windows Task Manager • Applications tab

– The Applications tab in Task Manager shows a list of programs currently running.

– Choosing to End Task from the Applications tab causes a request to be sent to the application for it to terminate.

• Processes tab– The Processes tab shows a list of all running processes

on the system. This list includes services and processes from other accounts.

• Performance tab– The performance tab shows overall statistics about the

systems performance, most notably the overall amount of CPU usage and how much memory is being used.

• Networking tab– The Networking tab shows statistics relating to each of

the network adapters present in the computer. By default the adapter name, percentage of network utilization, link speed and state of the network adapter are shown, along with a histogram of recent activity. More options can be shown by choosing Select columns... from the View menu.

04/21/23 39

MSCONFIG • Built into Windows is a special tool called

the "Microsoft System Configuration Utility" or simply "MSCONFIG." – MSCONFIG can be used to ensure that your

computer boots faster and crashes less. • Most people know that the more programs

you have running on your computer at once, the more likely it is that your computer will either run slowly or even crash. – What most people don't know is that every

time you boot your computer a whole mess of "hidden" programs load in the background.

– Some of these hidden programs are essential, but most aren't.

– Turning off some of these hidden programs can significantly increase your computer's performance and reliability.

04/21/23 40

MSCONFIG: XP

Microsoft Windows Vista

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

Trends from 1990 to today…

• Faster

• Smaller

• More reliable

• Less expensive

• Easier to use