Fall Lecture 1. Operating Systems: Configuration & Use CIS345. Introduction to Operating Systems. Mostafa Z. Ali.

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Operating Systems: Configuration & Use

CIS345

Mostafa Z. Ali

Fall 2009

Introduction to Operating Systems

Lecture 1

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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

Chapter

1

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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

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• 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

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• What Types of Microcomputers Are Used Today?

– Desktops and laptops

– Servers – provide services to other computers – Handheld devices – designed for a specific

purpose

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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

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• Microprocessor ^(continued)

– Since the 386DX, Intel Microprocessors support three modes:

• Real mode

• 286 protected mode

• 386 protected mode

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• Microprocessor (continued)

– Real mode

• Intel processors power up in this mode

• Total address space = 1MB

• 640KB limit for OS and application

• Single‐tasking

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– 286 protected mode

• Total address space = 16 MB

• Can multitask certain applications

• Does not support virtual machines

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– 386 protected mode

• Total address space = 4GB

• Supports the use of virtual machines

• Multitasking

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– 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

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• 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

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• Memory

– Chips that store programs and data – Random‐access memory (RAM)

– Read‐only memory (ROM)

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• 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

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• 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

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• 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

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• 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

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• Keyboard

– An input device with a typewriter style layout of alphanumeric and punctuation keys

– Includes additional function, control, arrow, and editing keys

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• 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

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• 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

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• Peripheral Devices

– Broad term for nonessential add‐on devices – Includes printers, scanners, pointing devices,

digital cameras, external modems, and disk drives

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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

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• Operating System Functions

– User interface

– Job management – Task management

– Memory Management – File management

– Device management – Security

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• 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

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• 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

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• Memory Management

– Manages placement of programs and data in memory

– Virtual memory manager moves code and data to virtual memory (file on hard drive)

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• 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

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• 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

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• 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

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• Categories of Operating Systems

– Single‐User/Single‐tasking – Single‐User/Multitasking – Multi‐User/Multitasking – Real‐Time

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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

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• 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

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• 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

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• 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.

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• 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

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• 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

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• 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

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Desktop OSs Available Today

• DOS from Microsoft

• Windows NT

• Windows 98

• Windows ME

• Windows 2000

• Windows XP

• Macintosh OSs

• UNIX

• Linux

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• 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

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• 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

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• 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)

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• 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

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• 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

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• 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

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• 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

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• Macintosh Operating Systems

– Designed to run on Apple Macintosh computers, but “can be” installed on a regular PC (Intel‐based) – Mac OS X Leopard, and Mac OS X Snow Leopard

are common today

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• Macintosh Operating Systems (continued)

– Macintosh computers generally use the PowerPC chip with an architecture that is enhanced for

graphics and multimedia

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• 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

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• 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

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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)

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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

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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

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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

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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

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Chapter Summary

– 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.

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Chapter Summary

– 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

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Chapter Summary

– 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

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Chapter Summary

– 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

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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

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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 X, and several versions of UNIX and Linux

– Each of today’s common operating systems is best suited for certain uses

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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