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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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)

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

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

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

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

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

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

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

Yesterday’s Operating Systems The Second Wave (second killer app) Lotus 1-2-3 – a DOS spreadsheet application that is fast and provides added functionalities Lotus 1-2-3 became the killer app for the IBM-PC/PC DOS combination.

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

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

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

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

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

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

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)

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

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

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 2000 Server, Windows 2000 Advanced Server, and Windows 2000 Enterprise Edition

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

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

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

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

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

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)

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

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

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

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

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.

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

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

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

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

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

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