2. Introduction to Operating Systems
Chapter 1
Introduction to Operating Systems
An Overview of Microcomputers
What’s Contained in and Attached to a Microcomputer?
Purpose, Types, and Functions of Microcomputer Operating Systems
Yesterday’s Operating Systems
Desktop OSs Available Today

3. Learning Objectives Describe the microcomputers in use today
Identify common computer hardware components
Describe the purpose and functions of microcomputer operating systems
Describe major events in the evolution of microcomputer operating systems
List and compare the common microcomputer operating systems

4. An Overview of Microcomputers
What is a Microcomputer?
A computer built around a microprocessor
Microprocessor performs calculations or processing
A personal computer (PC) is a microcomputer that complies with hardware standards set and supported by Microsoft and Intel

5. An Overview of Microcomputers
What Types of Microcomputers Are Used Today?
Desktops and laptops
Servers – provide services to other computers
Handheld devices – designed for a specific purpose

6. What’s Contained in and Attached to a Microcomputer?
Microprocessor
Also known as the CPU or processor
Central component of a microcomputer
Performs calculations
One or more per microcomputer

7. What’s Contained in and Attached to a Microcomputer?
Microprocessor (continued)
Since the 386DX, Intel Microprocessors support three modes:
Real mode
286 protected mode
386 protected mode

8. What’s Contained in and Attached to a Microcomputer?
Microprocessor (continued)
Real mode
Intel processors power up in this mode
Total address space = 1MB
640KB limit for OS and application
Single-tasking

9. What’s Contained in and Attached to a Microcomputer?
Microprocessor (continued)
286 protected mode
Total address space = 16 MB
Can multitask certain applications
Does not support virtual machines

10. What’s Contained in and Attached to a Microcomputer?
Microprocessor (continued)
386 protected mode
Total address space = 4GB
Supports the use of virtual machines
Multitasking

11. What’s Contained in and Attached to a Microcomputer?
Microprocessor (continued)
Processors can work with 8-bit, 16-bit, 32-bit, and 64-bit chunks of data
The number of bits (binary digits) is the size of data that can be processed at one time

12. What’s Contained in and Attached to a Microcomputer?
Motherboard and Chipset
Motherboard – central circuit board
Contains one or more CPU slots or sockets into which the processor is plugged
Chipset, memory slots, voltage regulator module (VRM), ROM BIOS, and the expansion bus slots are components of a motherboard
Chipset controls the flow of signals to and from the processor and other components

13. What’s Contained in and Attached to a Microcomputer?
Memory
Chips that store programs and data
Random-access memory (RAM)
Read-only memory (ROM)

14. What’s Contained in and Attached to a Microcomputer?
Memory (continued)
RAM
System, main, or physical memory
Used by active programs
One or more circuit cards with memory chips
Volatile – all is lost when the computer is powered off

15. What’s Contained in and Attached to a Microcomputer?
Memory (continued)
ROM BIOS
Stores programs permanently
Called ‘firmware’ since it is non-volatile
ROM BIOS contains:
Code for starting the computer
Code for controlling communications between the processor and other components
A setup program for configuring system options
Configuration information stored in a special kind of non-volatile RAM called the CMOS RAM

16. What’s Contained in and Attached to a Microcomputer?
ROM BIOS configuration information
Disk drive types and capacity
Disk boot order
System memory
Connectors (ports)
Power management
Other information determined by motherboard and ROM BIOS manufacturers

17. What’s Contained in and Attached to a Microcomputer?
Video Adapter and Display
Video adapter – circuitry that sends the controlling output signals to the display screen
Display screen – a monitor or a flat panel display (FPD) for visual output from the computer

18. What’s Contained in and Attached to a Microcomputer?
Keyboard
An input device with a typewriter style layout of alphanumeric and punctuation keys
Includes additional function, control, arrow, and editing keys

19. What’s Contained in and Attached to a Microcomputer?
Pointing Device
Required to move a graphical pointer (cursor) around in a GUI
Mouse is the most common pointing device – connects via a physical cable or a wireless connection.
Other pointing devices: touch pad, track ball, joystick, and light pen

20. What’s Contained in and Attached to a Microcomputer?
Disk Drives
Store data and programs
Encoded on surface of small spinning platters
Magnetic or optical technology
Floppy drives and hard disk drives use magnetic technology
Compact disk (CD) and digital versatile disk (DVD) drives use optical technologies

21. What’s Contained in and Attached to a Microcomputer?
Peripheral Devices
Broad term for nonessential add-on devices
Includes printers, scanners, pointing devices, digital cameras, external modems, and disk drives

22. Purpose, Types, and Functions of Microcomputer Operating Systems
What is an Operating System?
An Operating System is:
The central control program for a computer
The intermediary between applications & hardware

23. Purpose, Types, and Functions of Microcomputer Operating Systems
Operating System Functions
User interface
Job management
Task management
Memory Management
File management
Device management
Security

24. Purpose, Types, and Functions of Microcomputer Operating Systems
User Interface
AKA the ‘shell’
A software layer for user interaction
Includes the command processor
Includes the visual components of the OS
Character-based command line
GUI

25. Purpose, Types, and Functions of Microcomputer Operating Systems
Job management
Controls the order and time in which programs are run
Task management
Found in multitasking operating systems
Controls the focus
Allows user to switch between tasks

26. Purpose, Types, and Functions of Microcomputer Operating Systems
Memory Management
Manages placement of programs and data in memory
Virtual memory manager moves code and data to virtual memory (file on hard drive)

27. Purpose, Types, and Functions of Microcomputer Operating Systems
File Management
AKA data management
Allows the OS to read, write, and modify data
Data is organized into files
Allows users to organize their files into containers called folders or directories

28. Purpose, Types, and Functions of Microcomputer Operating Systems
Device Management
Controls hardware through device drivers
A device driver is unique to a device
Created by the manufacturer of the device to work with a specific operating system

29. Purpose, Types, and Functions of Microcomputer Operating Systems
Security
Provides password-protected authentication of the user before allowing access
Checks user name and password
Restricts the actions that can be performed on a computer, customized for each user

30. Purpose, Types, and Functions of Microcomputer Operating Systems
Categories of Operating Systems
Single-User/Single-tasking
Single-User/Multitasking
Multi-User/Multitasking
Real-Time

31. Yesterday’s Operating Systems
First the machines…
Charles Babbage designed the first computer in the 1820s
Apple II was the first microcomputer to combine critical elements like keyboard, monitor, operating system, and desirable and useful applications

32. Yesterday’s Operating Systems
Then the Operating Systems
Early single-purpose computers included system functions
OSs did not exist as separate entity
OSs evolved from need for multipurpose computers

33. Yesterday’s Operating Systems
DOS, CP/M, Apple, and the Killer App
To be widely accepted a computer needed a ‘killer app’
VisiCalc was the killer app of 1970’s micro- computers
VisiCalc ran under the CP/M OS
VisiCalc contributed to the success of the Apple II
Both PC DOS and a version of CP/M were available for the IBM PC

34. Yesterday’s Operating Systems
The Second Wave (second killer app)
Lotus – a DOS spreadsheet application that is fast and provides added functionalities
Lotus became the killer app for the IBM-PC/PC DOS combination.

35. Yesterday’s Operating Systems
OS/2 (Operating System/2)
Version 1.0 introduced in 1987
Developed by Microsoft and IBM
1.0 had costly memory and disk requirements
IBM introduced OS/2 Warp in 1990’s
IBM has ended development of new versions

36. Yesterday’s Operating Systems
Microsoft Windows
1985 first version – GUI on top of DOS
Windows 3.0, introduced in 1990, provided better support for legacy DOS applications
Windows 3.x works in real mode, standard mode, and 386 enhanced mode
1992 Windows 3.1 successful with MS Office

37. Yesterday’s Operating Systems
Windows for Workgroups
DOS and earlier versions of Windows had no networking
Windows for Workgroups 3.1 and 3.11 enabled peer-to-peer networking

38. Desktop OSs Available Today
DOS from Microsoft
Windows NT
Windows 98
Windows ME
Windows 2000
Windows XP
Macintosh OSs
UNIX
Linux

39. Desktop OSs Available Today
DOS from Microsoft
DOS provides support for interaction with disk drives
Microsoft’s first version of DOS, called PC DOS
Introduced with the first IBM-PC in 1981
Each major version of DOS supported new disk capacities
DOS has a text-mode command line interface

40. Desktop OSs Available Today
Windows NT
First Microsoft OS to take full advantage of the capabilities of the Intel’s 386 protected mode
Two main versions of NT – one for servers and another for desktop computers
Windows NT 4.0, introduced in 1996, has a GUI similar to Windows 95

41. Desktop OSs Available Today
Windows 98
An evolutionary development compared to the earlier Windows operating system in terms of GUI and integrated components
New options for customizing the GUI, including tighter integration with Microsoft’s Web browser, Internet Explorer (IE)

42. Desktop OSs Available Today
Windows 98 (continued)
Comes with drivers and support for devices like DVD drives
It was the choice for PCs with plug and play (PnP) hardware, not supported by Windows NT

43. Desktop OSs Available Today
Windows Me
Introduced in 2000 as an upgrade to Windows 98
Improved music, video, and home networking support
Provides utilities as well as applications for dealing with PC software configuration, digital music, and video

44. Desktop OSs Available Today
Windows 2000
Family of OS products, introduced in 2000
Combines the best of Windows 98 and Windows NT
Windows 2000 Professional, Windows Server, Windows 2000 Advanced Server, and Windows 2000 Enterprise Edition

45. Desktop OSs Available Today
Windows XP
Several products, but no server version
Most common are Windows XP Home Edition and Windows XP Professional
Improved GUI as well as several network- and security-related features
Default desktop only contains the Recycle Bin

46. Desktop OSs Available Today
Macintosh Operating Systems
Only run on Apple Macintosh computers
Mac OS 9 and Mac OS X common today

47. Desktop OSs Available Today
Macintosh Operating Systems (continued)
Macintosh hardware and software are proprietary products of Apple Computer Company
Macintosh computers generally use the PowerPC chip with an architecture that is enhanced for graphics and multimedia

48. Desktop OSs Available Today
UNIX
Introduced by Bell Labs Computing Science Research Center (Bell Labs) as UNIX Version 6 in 1975
A portable operating system for mini-computers and mainframe computers
Supports timesharing and multi-user systems
An excellent server operating system as it utilizes resources carefully, allowing only the required services to be loaded

49. Desktop OSs Available Today
UNIX (continued)
The current commercial versions of UNIX include Sun Microsystems’ Solaris, Hewlett- Packard’s HP-UX, IBM’s AIX, and Compaq’s Tru64 UNIX
Many open source versions of UNIX are also available, which can be changed according to requirements

50. Desktop OSs Available Today
Linux
Modeled on UNIX
Named for original developer, Linus Benedict Torvalds
Begun in 1991 by Torvalds and others as open- source for modern computers.
Written in the C language using GNU C Compiler (GCC)

51. Desktop OSs Available Today
Linux (continued)
Distributed free
Vendors sell bundles with extras (utilities, GUIs, manuals)
Novell, Red Hat, and others distribute such bundles
Fastest-growing computer server OS
Making inroads on desktop computers

52. Chapter Summary Microcomputers Today
A computer consists of hardware, applications software, and operating system software
The operating system allows the user to interact with the computer hardware

53. Chapter Summary Common Microcomputer Hardware
The basic components of a microcomputer are processor, motherboard, memory, video adapter and display, keyboard, pointing device, disk drives, and peripheral devices
You can identify hardware components by a visual inspection, by observing information displayed during the boot up process, and by accessing a ROM BIOS setup program

54. Chapter Summary
Purpose and Functions of Microcomputer Operating systems
Certain functions are provided by most, if not all, current operating systems. These functions include a user interface, job management, task management, memory management, file manage-ment, device management, and security.
The operating system makes everything work together

55. Chapter Summary
Purpose and Functions of Microcomputer Operating systems
You can identify most of the functions provided by your operating system by careful observation. For instance, evidence of support of the security function includes a required logon procedure when you start your computer, and the need for authorization to access resources on your local computer.

56. Chapter Summary
Purpose and Functions of Microcomputer Operating systems
There are four categories of operating systems:
Single-User/single-tasking
Single-User/multitasking
Multi-User/multitasking
Real-Time
A Single-User/single-tasking operating system is one that allows only a single user to perform a single task at a time

57. Chapter Summary
Purpose and Functions of Microcomputer Operating systems
An operating system that allows a single user to perform two or more functions at once is a Single-User/multitasking operating system
A Multi-User/multitasking operating system is an operating system that allows multiple users to run programs simultaneously on a single network server, called a terminal server

58. Chapter Summary
Purpose and Functions of Microcomputer Operating systems
Real-time operating systems are defined by their speed and ability to work with special real-time applications programs. A Real-time operating system is a very fast, relatively small OS that is often embedded, meaning it is built into the circuitry of a device and not normally loaded from a disk drive

59. Chapter Summary
Major Events in the Evolution of Microcomputer Operating Systems
The history of current microcomputers and their OSs involved many technical advances and the imagination of a multitude of innovative people
You can find many accounts of the history of computers and operating systems by searching the Internet

60. Chapter Summary What OSs Are Available Today?
The microcomputer operating systems common today include MS-DOS, several versions of Windows (Windows 98, Windows 2000, and Windows XP), Mac OS 9, Mac OS X, and several versions of UNIX and Linux
Each of today’s common operating systems is best suited for certain uses

61. Chapter Summary What OSs Are Available Today?
Microsoft desktop OSs are common in the business environment
Both UNIX and Linux can be found on high- end servers and on desktop computers. The use of Linux is growing on all types of systems
The Mac OSs are commonly used in education and in graphic workstations