Introduction to Operating Systems Chapter 1 Introduction to Operating Systems McGraw-Hill

Learning Objectives LO 1.1 Describe the purpose and functions of operating systems LO 1.2 Describe major events in the evolution of operating systems LO 1.3 List and compare the common operating systems in use today

An Overview of Operating Systems What is a Microcomputer? A computer built around a microprocessor Microprocessor is a special integrated circuit (IC) that performs calculations and processing An IC (chip) is a small electronic component made up of transistors and other miniaturized parts Microprocessor also called central processing unit (CPU) Many other ICs in a computer

A typical PC with components

An Overview of Operating Systems What’s Inside a Microcomputer? A least one CPU Motherboard RAM ROM BIOS Also attached Keyboard Display Printer Pointing Device and much more

An Overview of Operating Systems What’s Inside a Microcomputer? More About ROM BIOS Program code for basic control of devices Many components contain additional ROM BIOS Device drivers install in OS for each device ROM BIOS includes power-on-self test (POST)

Figure 1-1 An example of a BIOS start-up message

An Overview of Operating Systems What’s Types of Microcomputers are in Use Today? Desktops and Laptops Servers Handheld Devices Growing number and types Most popular are smartphones (iPhone, BlackBerry, etc.)

A PC laptop

Two MacBook laptops

An Overview of Operating Systems Functions of Operating Systems An Operating System is: The central control program(s) for a computer Loads when computer is turned on Kernel (main component) remains in memory Manages low-level OS tasks Acts as intermediary between applications & hardware

An Overview of Operating Systems Functions of Operating Systems User interface Job management Task management Memory Management File management Device management Security

The functions of an operating system

An Overview of 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

Figure 1-2 MS-DOS prompt

Figure 1-3 A typical GUI screen

An Overview of 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

An Overview of 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)

An Overview of 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

An Overview of 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

An Overview of 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

An Overview of Operating Systems Categories of Operating Systems Single-User/Single-tasking Single-User/Multitasking Multi-User/Multitasking Real-Time 16-, 32-, and 64-bit OSs

Figure 1-4 Single-user/single-tasking

Figure 1-5 Single-user/multitasking

Figure 1-6 Multiuser/multitasking

Figure 1-7 Example of a device containing a real-time embedded system

Table 1-1 Windows Memory Limits

Yesterday’s Operating Systems UNIX–The OS for All Platforms 1975: UNIX version 6 emerged from Bell Labs Computing Science Research Center (Bell Labs) OS for many platforms Free versions: BSD, Net BSD, Open BDS, & Open Solaris. Commercial versions: AIX, OpenServer (derived from SCO UNIX), & HP/UX Traditional CLI shell GNOME and KDE GUIs

Yesterday’s Operating Systems The Evolution of Microcomputer OSs (cont.) Theoretical designs started as early as the 1820’s Early computers were single-purpose, with no need for OS 1970s: TRS-80 and Apple II microcomputers OSs evolved from need for multipurpose computers

Yesterday’s Operating Systems The Evolution of Microcomputer OSs (cont.) The Killer App VisiCalc spreadsheet helped sell the Apple II First IBM-PC sold without a killer app DOS outsold CP/M for IBM-PC due to pricing The Second Killer App Lotus 1-2-3, a DOS-based spreadsheet Created need for IBM/PC VisiCalc ran on the CP/M OS

Figure 1-8 Lotus 1-2-3 spreadsheet

Yesterday’s Operating Systems The Evolution of Microcomputer OSs (cont.) Apple OS for Apple I and Apple II (non-GUI) 1976: Steve Jobs created Apple I and founded Apple Computer 1977: Apple introduces Apple II at the West Coast Computer Faire in San Francisco 1978: Added disk drives for Apple II GUI Apple OSs 1982: Apple Lisa computer 1984: Macintosh computer

Yesterday’s Operating Systems The Evolution of Microcomputer OSs (cont.) GUI Apple OSs (cont.) 1999: Mac OS 9 Multi-user Weak in memory management and multitasking 2001: Mac OS X First Mac OS based on UNIX Has both a GUI and a CLI

Yesterday’s Operating Systems The Evolution of Microcomputer OSs (cont.) MS-DOS 1981: IBM-PC with PC-DOS by Microsoft Single-tasking with very limited memory support No native GUI No built-in security functions Microsoft developed several versions of MS-DOS

Figure 1-9 MS-DOS prompt with the Format command

Yesterday’s Operating Systems The Evolution of Microcomputer OSs (cont.) OS/2 (Operating System/2) 1987: Version 1.0 introduced Developed by Microsoft and IBM 1.0 had costly memory and disk requirements 1990’s: IBM introduced OS/2 Warp mainly for servers 2003: IBM ended development of new versions 2004: IBM sold PC division to China-based Lenovo Group Students will learn more about DOS in Chapter 4.

Yesterday’s Operating Systems The Evolution of Microcomputer OSs (cont.) Microsoft Windows Version is a new level of Windows OS Edition is a unique product based on a version (several editions per version) 1985: Windows 1 – a GUI on top of DOS 1990: Windows 3.0 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

Figure 1-10 Windows 3.1 desktop

Yesterday’s Operating Systems The Evolution of Microcomputer OSs (cont.) Windows for Workgroups DOS and earlier versions of Windows had no built-in network support 1992: Windows for Workgroups 3.1 and 3.11 enabled peer-to-peer networking Still dependent on DOS

Yesterday’s Operating Systems The Evolution of Microcomputer OSs (cont.) Windows NT 1993: First Microsoft OS to take full advantage of the capabilities of the Intel 386 protected mode Two main versions of NT – one for servers and another for desktop computers 1996: Windows NT 4.0 with a GUI similar to Windows 95 Microsoft no longer sells or supports Windows NT

Figure 1-11 Windows NT 4.0 desktop with open windows

Yesterday’s Operating Systems The Evolution of Microcomputer OSs (cont.) Windows 95 1995: Windows 95 introduced; predated Windows NT Workstation A continuation of the Windows 3.X model: GUI on top of DOS Both 16-bit and 32-bit code A new GUI

Yesterday’s Operating Systems The Evolution of Microcomputer OSs (cont.) Windows 98 1998: An upgrade to Windows 95 More stable Greater integration with Internet Explorer More customization options Support for new devices like DVD drives Drawback: Lacked local security

Figure 1-12 MS Windows 98 desktop with open windows

Yesterday’s Operating Systems The Evolution of Microcomputer OSs (cont.) Windows Me 2000: An upgrade to Windows 98 Improved music, video, and home networking support Provided both utilities and applications for dealing with PC software configuration, digital music, and video Last Windows version based on Windows 95 kernel Targeted the home market

Yesterday’s Operating Systems The Evolution of Microcomputer OSs (cont.) Windows 2000 Windows 2000: Introduced in several editions Windows 2000 Professional (for desktops and laptops) Windows 2000 Server Windows 2000 Advanced Server Windows 2000 Enterprise Edition Combines the best of Windows 98 and Windows NT

Figure 1-13 MS Windows 2000 desktop

Yesterday’s Operating Systems The Evolution of Microcomputer OSs (cont.) Windows XP 2001: Several editions, but no server version Most common: Windows XP Home Edition Windows XP Professional (enhanced security features) Windows XP Media Edition Most editions were 32-bit Windows XP 64-bit Edition for Intel Itanium processor platform Support life cycle for XP is ending Support is ending, but XP is on many desktops, and will remain on many for a few more years.

Figure 1-14 MS Windows XP desktop with open windows

Table 1-2: Summary of Current Desktop OSs Today’s Desktop OSs Point out that the following chapters in this book go into more detail on the current desktop OSs (Windows Vista/7, Linux, and Mac OS X), as well as DOS. A chapter on Windows XP is also included because it still exists on many desktops. Only since the introduction of Windows 7 have we seen the number of Windows XP desktops begin to dwindle. Table 1-2: Summary of Current Desktop OSs

Today’s Desktop OSs Windows Vista 2007: A new GUI, other improvements But not widely adopted

Figure 1-15 The Windows Vista desktop

Today’s Desktop OSs Windows 7 Improvements that solved problems with Vista

Figure 1-16: The Windows 7 desktop

Today’s Desktop OSs Windows File Systems FAT file systems NTFS FAT12, FAT16, FAT32, exFAT Logical structure includes file allocation table and special files called directories NTFS Introduced in Windows NT In subsequent Windows except Windows 9x and Windows Me Supports very large disk volumes and security

Today’s Desktop OSs Windows File Systems File systems for optical drives CD-ROM File System (CDFS) Universal disk Format (UDF) Live File System

Today’s Desktop OSs Mac OS X Apple used proprietary hardware and software Mid-1990s to 2005: Apple used Motorola PowerPC 2005 to present: Intel platform Mac OS X is only licensed to run on Apple computers

Figure 1-17 Mac OS X GUI

Today’s Desktop OSs 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 the GNU C Compiler (GCC) Many free or inexpensive bundles

Today’s Desktop OSs Linux (cont.) Available in both 32-bit and 64-bit distributions Multitasking / multi-user Novell, Red Hat, and others distribute such bundles Fastest-growing computer server OS Making inroads on desktop computers Supports several file systems Old Minux, ext, ext2 Journaling in ext3, ReiserFS, JFS, XFS Point out that the Linux file systems offer file-level security.

Figure 1-18 Red Hat Linux directory listing (ls command)

Chapter 1 Summary LO1.1 An Overview of Operating Systems A computer consists of hardware and two types of software: operating system software and applications software. The operating system allows the user to interact with the computer hardware. Certain computer hardware is common to most computers. The basic components include the processor, motherboard, RAM, ROM BIOS, video adapter, display screen, keyboard, pointing device, and other peripherals.

Chapter 1 Summary LO1.1 An Overview of Operating Systems (cont.) Common computers in use today include desktops, laptops, server systems, and handheld devices. Most, if not all, current operating systems provide a user interface, job management, task manage-ment, memory management, file management, device management, and security. There are four categories of operating systems: single-user / single-tasking, single-user / multi-tasking, multiuser/multitasking, and real-time.

Chapter 1 Summary LO1.1 An Overview of Operating Systems (cont.) Today’s popular operating systems for desktops and laptops come in versions for 32-bit and 64-bit processing. The biggest advantage of a 64-bit OS over a 32-bit version of the same OS is that the amount of memory supported is much greater in a 64-bit OS.

Chapter 1 Summary LO 1.2 Yesterday’s Operating Systems The history of current computers and their OSs involved many technical advances and the imagination of a multitude of innovative people. UNIX is the oldest popular operating system and comes in versions for very large computers, as well as microcomputers. It is a portable OS that is usable on a variety of computer system platforms, with only minor alterations required for the underlying architecture.

Chapter 1 Summary LO 1.2 Yesterday’s Operating Systems (cont.) Early microcomputers included the MITS Altair 8800, the Apple I and Apple II, Radio Shack’s TRS-80, and the Commodore, all introduced in the 1970s. The Apple computers came with the Apple OS. Certain “killer apps,” notably VisiCalc and Lotus 1-2-3, made microcomputers appeal to ordinary people who were attracted to programs that automated formerly manual tasks

Chapter 1 Summary LO 1.2 Yesterday’s Operating Systems (cont.) IBM introduced the PC in 1981, and it far exceeded the expectations of IBM with Microsoft BASIC in ROM and PC DOS for computers with a floppy disk drive. Microsoft made MS-DOS available to third-party PC manufacturers. Microsoft Windows evolved from the first version in 1985 to Windows 7, introduced in 2009.

Chapter 1 Summary LO 1.2 Yesterday’s Operating Systems (cont.) The Apple Mac computer, introduced in 1984, came with the MAC OS System. This OS line continued through Mac OS 9, introduced in 1999, and phased out after Mac OS X was introduced 2001

Chapter 1 Summary LO 1.3 Today’s Desktop Operating Systems The operating systems common today include Windows XP, Windows Vista, Windows 7, Mac OS X, and Linux. Windows supports several file systems for hard drives and optical disks. The most feature-rich and secure file system for hard drives is the NTFS file system.

Chapter 1 Summary LO 1.3 Today’s Desktop Operating Systems (cont.) Mac OS X, based on NextStep, an OS with a UNIX kernel, runs only on Apple Macintosh computers, and while it supports several file systems, the preferred file system for hard drives is HFS+. Linus Torvalds developed Linux as a collaborative effort beginning in 1991. A full multitasking / multiuser operating system, it is available in both 32-bit and 64-bit distributions and can run on nearly any computer.

Chapter 1 Summary LO 1.3 Today’s Desktop Operating Systems (cont.) Linux supports several file systems for hard drives and optical disks. The most feature-rich and secure file system for hard drives is the ext3 file system.