Introduction to Operating Systems
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Transcript of Introduction to Operating Systems
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Introduction to Operating Systems
An Overview of MicrocomputersWhat’s Contained in and Attached to a Microcomputer?
Purpose, Types, and Functions of Microcomputer Operating Systems
Yesterday’s Operating SystemsDesktop OSs Available Today
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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
operating systems
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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
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 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
286 protected mode Total address space = 16 MB Can multitask certain applications Does not support virtual machines
386 protected mode Total address space = 4GB Supports the use of virtual machines Multitasking
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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
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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
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What’s Contained in and Attached to a Microcomputer? Memory
Chips that store programs and data Random-access memory (RAM) Read-only memory (ROM)
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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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
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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
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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
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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
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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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
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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
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What is an Operating System? An Operating System is:
The central control program for a computer The intermediary between applications & hardware
Operating System Functions User interface Job management Task management Memory Management File management Device management Security
Purpose, Types, and Functions of Microcomputer Operating Systems
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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
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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
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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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
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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
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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
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Purpose, Types, and Functions of Microcomputer Operating Systems
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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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
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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
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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.
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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
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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
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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
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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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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
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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
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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
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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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
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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
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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
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Desktop OSs Available Today
Macintosh Operating Systems Only run on Apple Macintosh computers Mac OS 9 and Mac OS X common today 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
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Desktop OSs Available Today
UNIX Introduced by Bell Labs Computing Science
Research Center (Bell Labs) as UNIX Ver 6 in 1975 A portable operating system for mini-computers and mainframes Supports timesharing and multi-user systems An excellent server operating system as it utilizes resources
carefully, allowing only the required services to be loaded 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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Desktop OSs Available Today
Linux Modeled on UNIX Named for original developer, Linus Torvalds Begun in 1991 by Torvalds and others as open-
source for modern computers. Written in the C language using GNU C Compiler (GCC) 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 MicrocomputerOperating 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
Purpose and Functions of MicrocomputerOperating 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.
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Chapter Summary
Purpose and Functions of MicrocomputerOperating 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
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Chapter Summary
Purpose and Functions of MicrocomputerOperating 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
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Chapter Summary
Purpose and Functions of MicrocomputerOperating 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
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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 9, 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