Transcript Chapter 5: System Hardware

System Software
Chapter 5
The Director
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Overview
• System software
• Applications software
• System software
components
• Platforms
• Web and Java
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What is system software and
applications software?
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System Software
• Works behind the scene
– starts up computer
– provides interface between the machine
language the computer understands and
hardware and applications
– system software must be loaded into RAM at
start up
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Applications Software
• Designed for user’s requirements
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word processing
spreadsheets
database management
graphics
multimedia
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Applications Software
• Productivity software
– word processing, spreadsheet, financial
management, database management,
communications, suites, browsers
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Business/specialty software
Education reference software
Home/personal software
Entertainment software
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System Software Components
• What functions
does system
software
perform?
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Basics
• Interprets data and
instructions
• Communicates with
peripherals
• Manages files
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System Software Components
• Operating system
• Utilities
• Language translators
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OS
• Master programs
– supervisor in RAM
– auto loads during boot routine using the master
boot record on the primary hard disk
– POST performed
• Software interfaces to hardware frequently remain
resident
• BIOS manages keyboard, screen, drives, ports,
time, and date
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OS
• BIOS stored on one or
more ROM chips
• Later editions of BIOS
may be flash updated
according to
motherboard
manufacturer’s
instructions
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Managing Programs and Data
• Multitasking (single
user)
– concurrent program
running
– foreground and
background running
• Multiprogramming
(multi-user)
– concurrent use by
different users
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Managing Programs (continued)
• Time-sharing
– time slicing tasks
• Multiprocessing
– simultaneous processing of two or more programs by
multiple processors
• coprocessing
• parallel processing, sharing memory
– called fault-tolerant systems
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Memory Management
• Virtual memory
– hard disk space
– when processor needs more
RAM space, swaps data onto
designated hard drive space
– improves flexibility but is
slower than RAM which has
direct access to the processor
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Drivers
• Handle I/O for specific
hardware
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Utilities Programs
• Utilities better than
those that are
native to an
operating system
can be purchased
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System Software Utilities
• Types
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backup: system, registry, e-mail, files
data recovery
virus protection
data compression
defragmentation
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Data Compression
• Lossy
– loss of accuracy, high degree of
compression
• Lossless
– retained accuracy but lower
compression ratios
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Lossy Compression
• JPEG
– Joint Photographers Experts Group
– video storage and editing but not for
transmission
• MPEG
– Motion Pictures Experts Group
– storage, editing, and transmission of video
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Lossless Compression
• PC
– PKZIP, WINZIP
– ARC
– PAK
.ZIP
.ARC
.PAK
• Mac
– StuffIt
– PackIt
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.SIT
.PIT
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Frag and Defrag
• Fragmentation refers to the storage
of a file in fragments in many
areas on a disk
• Defragmentation is a utility
process that endeavors to bring
each file into one whole area
within the disk, contiguously
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Language Translators
• These are the compilers and
interpreters used to connect
programs into machine
language to communicate
with the processor
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System Software Interfaces
• Command driven
• Unix, Linux
• Graphical User Interface (GUI)
• Microsoft:Windows 9x, Millennium/Neptune, NT,
and 2000
• MacOS
• GNOME interface to Linux
• use of icons, windows (little “w”), high use of
keyboard and mouse
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GUI
• Generally, GUI runs on top of
operating system to assist users
• Some memory is used to provide
the GUI
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OS Platforms
• How does
Windows
9x/Millennium/
Neptune
compare to
other operating
systems?
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Common OSs
• Mainframe
– IBM MVS, VM, DEC VAX/VMS
• Midframe
– IBM OS-400, Linux, Sun Solaris
• Network
– Novell NetWare, Lotus Dominoes, Microsoft
Windows NT
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Common Microprocessor OSs
• Microcomputer
– Microsoft Windows
9x/Millennium/Neptune
– Microsoft Windows NT/2000
– Linux
– Apple MacOS
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Windows
9x/Millennium/Neptune
• The first customer 32-bit
operating system
• Windows 98 and 98 SE
provide support for
printers, video cards, DVD,
and USB
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Windows NT
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Network system
Scalable to large local area network
Multitasking, multiprocessing, multiuser
Windows NT Workstation
– 1-2 processors
• Windows NT Server
– up to 32 processors
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Other Windows OSs
• Windows CE provides support for palmtop
computers
• Windows Millenium, due third quarter
2000, could be the last stand-alone
consumer version of Windows 9x, with
Windows 2000 in various capabilities
coming to the forefront
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OS/2 Warp
• OS/ 2 never established an
installed base large enough to
attract application developers
• Poor marketing, but still
supported
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UNIX
• Portable and scalable
• Can handle large volumes,
such as needed on large
Web sites
• Strong in medium-to-large
businesses
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Linux
• Linux emulates UNIX
• Many UNIX programs have been ported to
Linux
• Open development
– can recompile source code
• Single user and small to medium Web
server support
• Since code written for 386, can rehabilitate
older systems out of use
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NetWare
• Established network operating system with
strong printer and application server
functions
• Small business edition for up to 25 users
priced under NT
• Can sustain e-mail traffic through IPX
protocol
• NT gain in ground, but NetWare a strong
base
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Web
• What is a network
computer, and
how does it
involve the
Internet and Java?
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Specialization
• Isolation of customer
and corporate needs
• Software versions by
operating systems
• Emergence of accessing
applications and systems
online not just web
pages
– idea of renting
applications only for
time used
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Bloatware
• Large percentage of applications have
features not used
• Network PC
– approximates mainframe terminal
– sometimes with limited additional capabilities
– also called thin client
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Progress Issue: Bandwidth
• Sun’s control of Java Virtual
Machine diminishing as
computer companies provide
optimized VM
• Bandwidth increasing
substantially through cable,
digital subscriber service (DSL)
on telephone lines, and the
potential of more low-level
satellites
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Java
• Developed by James Gosling’s
group at Sun
• Promise of compile-once, run
everywhere not totally realized
• Becoming more universal as run
times decrease
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Some Generalities
• UNIX and Windows NT on high-end
workstations
• Mac still used for intensive graphics and
desktop publishing
• While Linux will not run Microsoft Office,
such programs as ApplixWare provides
filters to Office 2000 files, so the
incompatability is disappearing
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