Transcript Purpose and Functions of Microcomputer

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Chapter
Introduction to Operating Systems
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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
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An Overview of Microcomputers
 What is a Microcomputer?
 A computer built around a microprocessor
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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
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Real mode
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286 protected mode
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386 protected mode
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 Microprocessor (continued)
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Real mode
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286 protected mode
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Intel processors power up in this mode
Total address space = 1MB
640KB limit for OS and application
Single-tasking
Total address space = 16 MB
Can multitask certain applications
Does not support virtual machines
386 protected mode
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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)
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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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What’s Contained in and
Attached to a Microcomputer?
 Motherboard and Chipset
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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)
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RAM
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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)
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ROM BIOS
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Stores programs permanently
Called ‘firmware’ since it is non-volatile
ROM BIOS contains:
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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
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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
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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
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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
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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
 Operating System Functions
 User interface
 Job management
 Task management
 Memory Management
 File management
 Device management
 Security
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Purpose, Types, and Functions
of Microcomputer Operating Systems
 User Interface
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AKA the ‘shell’
A software layer for user interaction
Includes the command processor
Includes the visual components of the OS
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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
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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
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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
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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
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Single-User/Single-tasking
Single-User/Multitasking
Multi-User/Multitasking
Real-Time
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Yesterday’s Operating Systems
 First the machines…
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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
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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
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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)
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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)
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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
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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
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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 2000
 Windows NT
 Windows XP
 Windows 98
 Macintosh OSs
 Windows ME
 UNIX
 Linux
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Desktop OSs Available Today
 DOS from Microsoft
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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
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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
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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
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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
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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
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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
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Modeled on UNIX
Named for original developer, Linus Torvalds
Begun in 1991 by Torvalds and others as opensource 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
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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
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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
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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 Microcomputer
Operating systems
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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 Microcomputer
Operating systems
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There are four categories of operating
systems:
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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 Microcomputer
Operating systems
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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 Microcomputer
Operating systems
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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
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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?
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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?
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Microsoft desktop OSs are common in the
business environment
Both UNIX and Linux can be found on highend 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
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